diff --git a/Cargo.lock b/Cargo.lock
index 0ba0ef4..d9ccc29 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -936,12 +936,9 @@ dependencies = [
 name = "tengri"
 version = "0.13.0"
 dependencies = [
- "crossterm",
- "tengri",
  "tengri_dsl",
  "tengri_input",
  "tengri_output",
- "tengri_proc",
  "tengri_tui",
 ]
 
diff --git a/dsl/src/dsl.rs b/dsl/src/dsl.rs
deleted file mode 100644
index f4eedaf..0000000
--- a/dsl/src/dsl.rs
+++ /dev/null
@@ -1,320 +0,0 @@
-use crate::*;
-use thiserror::Error;
-
-pub type ParseResult<T> = Result<T, ParseError>;
-
-#[derive(Error, Debug, Copy, Clone, PartialEq)] pub enum ParseError {
-    #[error("parse failed: not implemented")]
-    Unimplemented,
-    #[error("parse failed: empty")]
-    Empty,
-    #[error("parse failed: incomplete")]
-    Incomplete,
-    #[error("parse failed: unexpected character '{0}'")]
-    Unexpected(char),
-    #[error("parse failed: error #{0}")]
-    Code(u8),
-}
-
-pub trait TryFromDsl<'state, T>: Sized {
-    fn try_from_expr <'source: 'state> (
-        _state: &'state T, _iter: &mut TokenIter<'source>
-    ) -> Option<Self> {
-        None
-    }
-    fn try_from_atom <'source: 'state> (
-        state: &'state T, value: Value<'source>
-    ) -> Option<Self> {
-        if let Exp(0, mut iter) = value {
-            return Self::try_from_expr(state, &mut iter)
-        }
-        None
-    }
-}
-
-/// Map EDN tokens to parameters of a given type for a given context
-pub trait Context<'state, U>: Sized {
-    fn get <'source> (&'state self, _iter: &mut TokenIter<'source>) -> Option<U> {
-        None
-    }
-}
-
-impl<'state, T: Context<'state, U>, U> Context<'state, U> for &T {
-    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
-        (*self).get(iter)
-    }
-}
-
-impl<'state, T: Context<'state, U>, U> Context<'state, U> for Option<T> {
-    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
-        self.as_ref().map(|s|s.get(iter)).flatten()
-    }
-}
-
-/// Implement the const iterator pattern.
-#[macro_export] macro_rules! const_iter {
-    ($(<$l:lifetime>)?|$self:ident: $Struct:ty| => $Item:ty => $expr:expr) => {
-        impl$(<$l>)? Iterator for $Struct {
-            type Item = $Item;
-            fn next (&mut $self) -> Option<$Item> { $expr }
-        }
-        impl$(<$l>)? ConstIntoIter for $Struct {
-            type Kind = IsIteratorKind;
-            type Item = $Item;
-            type IntoIter = Self;
-        }
-    }
-}
-
-/// Provides a native [Iterator] API over the [ConstIntoIter] [SourceIter]
-/// [TokenIter::next] returns just the [Token] and mutates `self`,
-/// instead of returning an updated version of the struct as [SourceIter::next] does.
-#[derive(Copy, Clone, Debug, Default, PartialEq)]
-pub struct TokenIter<'a>(
-    pub SourceIter<'a>
-);
-
-impl<'a> TokenIter<'a> {
-    pub const fn new (source: &'a str) -> Self {
-        Self(SourceIter::new(source))
-    }
-    pub const fn peek (&self) -> Option<Token<'a>> {
-        self.0.peek()
-    }
-}
-
-impl<'a> Iterator for TokenIter<'a> {
-    type Item = Token<'a>;
-    fn next (&mut self) -> Option<Token<'a>> {
-        self.0.next().map(|(item, rest)|{self.0 = rest; item})
-    }
-}
-
-impl<'a> From<&'a str> for TokenIter<'a> {
-    fn from (source: &'a str) -> Self{
-        Self(SourceIter(source))
-    }
-}
-
-impl<'a> From<SourceIter<'a>> for TokenIter<'a> {
-    fn from (source: SourceIter<'a>) -> Self{
-        Self(source)
-    }
-}
-
-/// Owns a reference to the source text.
-/// [SourceIter::next] emits subsequent pairs of:
-///   * a [Token] and
-///   * the source text remaining
-///     * [ ] TODO: maybe [SourceIter::next] should wrap the remaining source in `Self` ?
-#[derive(Copy, Clone, Debug, Default, PartialEq)]
-pub struct SourceIter<'a>(pub &'a str);
-
-const_iter!(<'a>|self: SourceIter<'a>| => Token<'a> => self.next_mut().map(|(result, _)|result));
-
-impl<'a> From<&'a str> for SourceIter<'a> {
-    fn from (source: &'a str) -> Self{
-        Self::new(source)
-    }
-}
-
-impl<'a> SourceIter<'a> {
-    pub const fn new (source: &'a str) -> Self {
-        Self(source)
-    }
-    pub const fn chomp (&self, index: usize) -> Self {
-        Self(split_at(self.0, index).1)
-    }
-    pub const fn next (mut self) -> Option<(Token<'a>, Self)> {
-        Self::next_mut(&mut self)
-    }
-    pub const fn peek (&self) -> Option<Token<'a>> {
-        peek_src(self.0)
-    }
-    pub const fn next_mut (&mut self) -> Option<(Token<'a>, Self)> {
-        match self.peek() {
-            Some(token) => Some((token, self.chomp(token.end()))),
-            None => None
-        }
-    }
-}
-/// Static iteration helper.
-#[macro_export] macro_rules! iterate {
-    ($expr:expr => $arg: pat => $body:expr) => {
-        let mut iter = $expr;
-        while let Some(($arg, next)) = iter.next() {
-            $body;
-            iter = next;
-        }
-    }
-}
-
-pub const fn peek_src <'a> (source: &'a str) -> Option<Token<'a>> {
-    let mut token: Token<'a> = Token::new(source, 0, 0, Nil);
-    iterate!(char_indices(source) => (start, c) => token = match token.value() {
-        Err(_) => return Some(token),
-        Nil => match c {
-            ' '|'\n'|'\r'|'\t' =>
-                token.grow(),
-            '(' =>
-                Token::new(source, start, 1, Exp(1, TokenIter::new(str_range(source, start, start + 1)))),
-            '"' =>
-                Token::new(source, start, 1, Str(str_range(source, start, start + 1))),
-            ':'|'@' =>
-                Token::new(source, start, 1, Sym(str_range(source, start, start + 1))),
-            '/'|'a'..='z' =>
-                Token::new(source, start, 1, Key(str_range(source, start, start + 1))),
-            '0'..='9' =>
-                Token::new(source, start, 1, match to_digit(c) {
-                    Ok(c) => Value::Num(c),
-                    Result::Err(e) => Value::Err(e)
-                }),
-            _ => token.error(Unexpected(c))
-        },
-        Str(_) => match c {
-            '"' => return Some(token),
-            _ => token.grow_str(),
-        },
-        Num(n) => match c {
-            '0'..='9' => token.grow_num(n, c),
-            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
-            _ => token.error(Unexpected(c))
-        },
-        Sym(_) => match c {
-            'a'..='z'|'A'..='Z'|'0'..='9'|'-' => token.grow_sym(),
-            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
-            _ => token.error(Unexpected(c))
-        },
-        Key(_) => match c {
-            'a'..='z'|'0'..='9'|'-'|'/' => token.grow_key(),
-            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
-            _ => token.error(Unexpected(c))
-        },
-        Exp(depth, _) => match depth {
-            0 => return Some(token.grow_exp()),
-            _ => match c {
-                ')' => token.grow_out(),
-                '(' => token.grow_in(),
-                 _  => token.grow_exp(),
-            }
-        },
-    });
-    match token.value() {
-        Nil => None,
-        _ => Some(token),
-    }
-}
-
-pub const fn to_number (digits: &str) -> Result<usize, ParseError> {
-    let mut value = 0;
-    iterate!(char_indices(digits) => (_, c) => match to_digit(c) {
-        Ok(digit) => value = 10 * value + digit,
-        Result::Err(e) => return Result::Err(e)
-    });
-    Ok(value)
-}
-
-pub const fn to_digit (c: char) -> Result<usize, ParseError> {
-    Ok(match c {
-        '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
-        '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9,
-        _ => return Result::Err(Unexpected(c))
-    })
-}
-
-#[derive(Debug, Copy, Clone, Default, PartialEq)] pub struct Token<'source> {
-    pub source: &'source str,
-    pub start:  usize,
-    pub length: usize,
-    pub value:  Value<'source>,
-}
-
-#[derive(Debug, Copy, Clone, Default, PartialEq)] pub enum Value<'source> {
-    #[default] Nil,
-    Err(ParseError),
-    Num(usize),
-    Sym(&'source str),
-    Key(&'source str),
-    Str(&'source str),
-    Exp(usize, TokenIter<'source>),
-}
-
-impl<'source> Token<'source> {
-    pub const fn new (source: &'source str, start: usize, length: usize, value: Value<'source>) -> Self {
-        Self { source, start, length, value }
-    }
-    pub const fn end (&self) -> usize {
-        self.start.saturating_add(self.length)
-    }
-    pub const fn slice (&'source self) -> &'source str {
-        self.slice_source(self.source)
-        //str_range(self.source, self.start, self.end())
-    }
-    pub const fn slice_source <'range> (&'source self, source: &'range str) -> &'range str {
-        str_range(source, self.start, self.end())
-    }
-    pub const fn slice_source_exp <'range> (&'source self, source: &'range str) -> &'range str {
-        str_range(source, self.start.saturating_add(1), self.end())
-    }
-    pub const fn value (&self) -> Value {
-        self.value
-    }
-    pub const fn error (self, error: ParseError) -> Self {
-        Self { value: Value::Err(error), ..self }
-    }
-    pub const fn grow (self) -> Self {
-        Self { length: self.length.saturating_add(1), ..self }
-    }
-    pub const fn grow_num (self, m: usize, c: char) -> Self {
-        match to_digit(c) {
-            Ok(n) => Self { value: Num(10*m+n), ..self.grow() },
-            Result::Err(e) => Self { value: Err(e), ..self.grow() },
-        }
-    }
-    pub const fn grow_key (self) -> Self {
-        let mut token = self.grow();
-        token.value = Key(token.slice_source(self.source));
-        token
-    }
-    pub const fn grow_sym (self) -> Self {
-        let mut token = self.grow();
-        token.value = Sym(token.slice_source(self.source));
-        token
-    }
-    pub const fn grow_str (self) -> Self {
-        let mut token = self.grow();
-        token.value = Str(token.slice_source(self.source));
-        token
-    }
-    pub const fn grow_exp (self) -> Self {
-        let mut token = self.grow();
-        if let Exp(depth, _) = token.value {
-            token.value = Exp(depth, TokenIter::new(token.slice_source_exp(self.source)));
-        } else {
-            unreachable!()
-        }
-        token
-    }
-    pub const fn grow_in (self) -> Self {
-        let mut token = self.grow_exp();
-        if let Value::Exp(depth, source) = token.value {
-            token.value = Value::Exp(depth.saturating_add(1), source)
-        } else {
-            unreachable!()
-        }
-        token
-    }
-    pub const fn grow_out (self) -> Self {
-        let mut token = self.grow_exp();
-        if let Value::Exp(depth, source) = token.value {
-            if depth > 0 {
-                token.value = Value::Exp(depth - 1, source)
-            } else {
-                return self.error(Unexpected(')'))
-            }
-        } else {
-            unreachable!()
-        }
-        token
-    }
-}
diff --git a/dsl/src/dsl_context.rs b/dsl/src/dsl_context.rs
new file mode 100644
index 0000000..4acbf63
--- /dev/null
+++ b/dsl/src/dsl_context.rs
@@ -0,0 +1,40 @@
+use crate::*;
+
+pub trait TryFromDsl<'state, T>: Sized {
+    fn try_from_expr <'source: 'state> (
+        _state: &'state T, _iter: TokenIter<'source>
+    ) -> Option<Self> {
+        None
+    }
+    fn try_from_atom <'source: 'state> (
+        state: &'state T, value: Value<'source>
+    ) -> Option<Self> {
+        if let Exp(0, iter) = value {
+            return Self::try_from_expr(state, iter.clone())
+        }
+        None
+    }
+}
+
+pub trait TryIntoDsl<T>: Sized {
+    fn try_into_atom (&self) -> Option<Value>;
+}
+
+/// Map EDN tokens to parameters of a given type for a given context
+pub trait Context<'state, U>: Sized {
+    fn get <'source> (&'state self, _iter: &mut TokenIter<'source>) -> Option<U> {
+        None
+    }
+}
+
+impl<'state, T: Context<'state, U>, U> Context<'state, U> for &T {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
+        (*self).get(iter)
+    }
+}
+
+impl<'state, T: Context<'state, U>, U> Context<'state, U> for Option<T> {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
+        self.as_ref().map(|s|s.get(iter)).flatten()
+    }
+}
diff --git a/dsl/src/dsl_error.rs b/dsl/src/dsl_error.rs
new file mode 100644
index 0000000..40b687d
--- /dev/null
+++ b/dsl/src/dsl_error.rs
@@ -0,0 +1,15 @@
+use crate::*;
+use thiserror::Error;
+pub type ParseResult<T> = Result<T, ParseError>;
+#[derive(Error, Debug, Copy, Clone, PartialEq)] pub enum ParseError {
+    #[error("parse failed: not implemented")]
+    Unimplemented,
+    #[error("parse failed: empty")]
+    Empty,
+    #[error("parse failed: incomplete")]
+    Incomplete,
+    #[error("parse failed: unexpected character '{0}'")]
+    Unexpected(char), 
+    #[error("parse failed: error #{0}")]
+    Code(u8),
+}
diff --git a/dsl/src/dsl_iter.rs b/dsl/src/dsl_iter.rs
new file mode 100644
index 0000000..acdbe4b
--- /dev/null
+++ b/dsl/src/dsl_iter.rs
@@ -0,0 +1,157 @@
+//! The token iterator [TokenIter] allows you to get the
+//! general-purpose syntactic [Token]s represented by the source text.
+//!
+//! Both iterators are `peek`able:
+//!
+//! ```
+//! let src = include_str!("../test.edn");
+//! let mut view = tengri_dsl::TokenIter::new(src);
+//! assert_eq!(view.0.0, src);
+//! assert_eq!(view.peek(), view.0.peek())
+//! ```
+use crate::*;
+
+/// Provides a native [Iterator] API over the [ConstIntoIter] [SourceIter]
+/// [TokenIter::next] returns just the [Token] and mutates `self`,
+/// instead of returning an updated version of the struct as [SourceIter::next] does.
+#[derive(Copy, Clone, Debug, Default, PartialEq)] pub struct TokenIter<'a>(
+    pub SourceIter<'a>
+);
+
+impl<'a> TokenIter<'a> {
+    pub const fn new (source: &'a str) -> Self {
+        Self(SourceIter::new(source))
+    }
+    pub const fn peek (&self) -> Option<Token<'a>> {
+        self.0.peek()
+    }
+}
+
+impl<'a> Iterator for TokenIter<'a> {
+    type Item = Token<'a>;
+    fn next (&mut self) -> Option<Token<'a>> {
+        self.0.next().map(|(item, rest)|{self.0 = rest; item})
+    }
+}
+
+impl<'a> From<&'a str> for TokenIter<'a> {
+    fn from (source: &'a str) -> Self{
+        Self(SourceIter(source))
+    }
+}
+
+impl<'a> From<SourceIter<'a>> for TokenIter<'a> {
+    fn from (source: SourceIter<'a>) -> Self{
+        Self(source)
+    }
+}
+
+/// Owns a reference to the source text.
+/// [SourceIter::next] emits subsequent pairs of:
+///   * a [Token] and
+///   * the source text remaining
+///     * [ ] TODO: maybe [SourceIter::next] should wrap the remaining source in `Self` ?
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
+pub struct SourceIter<'a>(pub &'a str);
+
+const_iter!(<'a>|self: SourceIter<'a>| => Token<'a> => self.next_mut().map(|(result, _)|result));
+
+impl<'a> From<&'a str> for SourceIter<'a> {
+    fn from (source: &'a str) -> Self{
+        Self::new(source)
+    }
+}
+
+impl<'a> SourceIter<'a> {
+    pub const fn new (source: &'a str) -> Self {
+        Self(source)
+    }
+    pub const fn chomp (&self, index: usize) -> Self {
+        Self(split_at(self.0, index).1)
+    }
+    pub const fn next (mut self) -> Option<(Token<'a>, Self)> {
+        Self::next_mut(&mut self)
+    }
+    pub const fn peek (&self) -> Option<Token<'a>> {
+        peek_src(self.0)
+    }
+    pub const fn next_mut (&mut self) -> Option<(Token<'a>, Self)> {
+        match self.peek() {
+            Some(token) => Some((token, self.chomp(token.end()))),
+            None => None
+        }
+    }
+}
+
+pub const fn peek_src <'a> (source: &'a str) -> Option<Token<'a>> {
+    let mut token: Token<'a> = Token::new(source, 0, 0, Nil);
+    iterate!(char_indices(source) => (start, c) => token = match token.value() {
+        Err(_) => return Some(token),
+        Nil => match c {
+            ' '|'\n'|'\r'|'\t' =>
+                token.grow(),
+            '(' =>
+                Token::new(source, start, 1, Exp(1, TokenIter::new(str_range(source, start, start + 1)))),
+            '"' =>
+                Token::new(source, start, 1, Str(str_range(source, start, start + 1))),
+            ':'|'@' =>
+                Token::new(source, start, 1, Sym(str_range(source, start, start + 1))),
+            '/'|'a'..='z' =>
+                Token::new(source, start, 1, Key(str_range(source, start, start + 1))),
+            '0'..='9' =>
+                Token::new(source, start, 1, match to_digit(c) {
+                    Ok(c) => Value::Num(c),
+                    Result::Err(e) => Value::Err(e)
+                }),
+            _ => token.error(Unexpected(c))
+        },
+        Str(_) => match c {
+            '"' => return Some(token),
+            _ => token.grow_str(),
+        },
+        Num(n) => match c {
+            '0'..='9' => token.grow_num(n, c),
+            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
+            _ => token.error(Unexpected(c))
+        },
+        Sym(_) => match c {
+            'a'..='z'|'A'..='Z'|'0'..='9'|'-' => token.grow_sym(),
+            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
+            _ => token.error(Unexpected(c))
+        },
+        Key(_) => match c {
+            'a'..='z'|'0'..='9'|'-'|'/' => token.grow_key(),
+            ' '|'\n'|'\r'|'\t'|')' => return Some(token),
+            _ => token.error(Unexpected(c))
+        },
+        Exp(depth, _) => match depth {
+            0 => return Some(token.grow_exp()),
+            _ => match c {
+                ')' => token.grow_out(),
+                '(' => token.grow_in(),
+                 _  => token.grow_exp(),
+            }
+        },
+    });
+    match token.value() {
+        Nil => None,
+        _ => Some(token),
+    }
+}
+
+pub const fn to_number (digits: &str) -> Result<usize, ParseError> {
+    let mut value = 0;
+    iterate!(char_indices(digits) => (_, c) => match to_digit(c) {
+        Ok(digit) => value = 10 * value + digit,
+        Result::Err(e) => return Result::Err(e)
+    });
+    Ok(value)
+}
+
+pub const fn to_digit (c: char) -> Result<usize, ParseError> {
+    Ok(match c {
+        '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
+        '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9,
+        _ => return Result::Err(Unexpected(c))
+    })
+}
diff --git a/dsl/src/dsl_macros.rs b/dsl/src/dsl_macros.rs
new file mode 100644
index 0000000..93b2cea
--- /dev/null
+++ b/dsl/src/dsl_macros.rs
@@ -0,0 +1,46 @@
+/// Static iteration helper.
+#[macro_export] macro_rules! iterate {
+    ($expr:expr => $arg: pat => $body:expr) => {
+        let mut iter = $expr;
+        while let Some(($arg, next)) = iter.next() {
+            $body;
+            iter = next;
+        }
+    }
+}
+
+/// Implement the const iterator pattern.
+#[macro_export] macro_rules! const_iter {
+    ($(<$l:lifetime>)?|$self:ident: $Struct:ty| => $Item:ty => $expr:expr) => {
+        impl$(<$l>)? Iterator for $Struct {
+            type Item = $Item;
+            fn next (&mut $self) -> Option<$Item> { $expr }
+        }
+        impl$(<$l>)? ConstIntoIter for $Struct {
+            type Kind = IsIteratorKind;
+            type Item = $Item;
+            type IntoIter = Self;
+        }
+    }
+}
+
+#[macro_export] macro_rules! get_value {
+    ($state:expr => $token:expr) => {
+        if let Some(value) = $state.get(&$token.value) {
+            value
+        } else {
+            panic!("no value corresponding to {:?}", &$token.value);
+        }
+    }
+}
+
+#[macro_export] macro_rules! get_content {
+    ($state:expr => $token:expr) => {
+        if let Some(content) = $state.get_content(&$token.value) {
+            content
+        } else {
+            panic!("no content corresponding to {:?}", &$token.value);
+        }
+    }
+}
+
diff --git a/dsl/src/dsl_token.rs b/dsl/src/dsl_token.rs
new file mode 100644
index 0000000..e26ee93
--- /dev/null
+++ b/dsl/src/dsl_token.rs
@@ -0,0 +1,120 @@
+//! [Token]s are parsed substrings with an associated [Value].
+//!
+//! * [ ] FIXME: Value may be [Err] which may shadow [Result::Err]
+//! * [Value::Exp] wraps an expression depth and a [SourceIter]
+//!   with the remaining part of the expression.
+//!   * expression depth other that 0 mean unclosed parenthesis.
+//!   * closing and unopened parenthesis panics during reading.
+//!   * [ ] TODO: signed depth might be interesting
+//! * [Value::Sym] and [Value::Key] are stringish literals
+//!   with slightly different parsing rules.
+//! * [Value::Num] is an unsigned integer literal.
+//!```
+//! use tengri_dsl::{*, Value::*};
+//! let source = include_str!("../test.edn");
+//! let mut view = TokenIter::new(source);
+//! assert_eq!(view.peek(), Some(Token {
+//!     source,
+//!     start: 0,
+//!     length: source.len(),
+//!     value: Exp(0, TokenIter::new(&source[1..]))
+//! }));
+//!```
+use crate::*;
+
+#[derive(Debug, Copy, Clone, Default, PartialEq)] pub struct Token<'source> {
+    pub source: &'source str,
+    pub start:  usize, 
+    pub length: usize,
+    pub value:  Value<'source>,
+}
+
+#[derive(Debug, Copy, Clone, Default, PartialEq)] pub enum Value<'source> {
+    #[default] Nil,
+    Err(ParseError),
+    Num(usize),
+    Sym(&'source str),
+    Key(&'source str),
+    Str(&'source str),
+    Exp(usize, TokenIter<'source>),
+}
+
+impl<'source> Token<'source> {
+    pub const fn new (source: &'source str, start: usize, length: usize, value: Value<'source>) -> Self {
+        Self { source, start, length, value }
+    }
+    pub const fn end (&self) -> usize {
+        self.start.saturating_add(self.length)
+    }
+    pub const fn slice (&'source self) -> &'source str {
+        self.slice_source(self.source)
+        //str_range(self.source, self.start, self.end())
+    }
+    pub const fn slice_source <'range> (&'source self, source: &'range str) -> &'range str {
+        str_range(source, self.start, self.end())
+    }
+    pub const fn slice_source_exp <'range> (&'source self, source: &'range str) -> &'range str {
+        str_range(source, self.start.saturating_add(1), self.end())
+    }
+    pub const fn value (&self) -> Value {
+        self.value
+    }
+    pub const fn error (self, error: ParseError) -> Self {
+        Self { value: Value::Err(error), ..self }
+    }
+    pub const fn grow (self) -> Self {
+        Self { length: self.length.saturating_add(1), ..self }
+    }
+    pub const fn grow_num (self, m: usize, c: char) -> Self {
+        match to_digit(c) {
+            Ok(n) => Self { value: Num(10*m+n), ..self.grow() },
+            Result::Err(e) => Self { value: Err(e), ..self.grow() },
+        } 
+    }
+    pub const fn grow_key (self) -> Self {
+        let mut token = self.grow();
+        token.value = Key(token.slice_source(self.source));
+        token
+    }
+    pub const fn grow_sym (self) -> Self {
+        let mut token = self.grow();
+        token.value = Sym(token.slice_source(self.source));
+        token
+    }
+    pub const fn grow_str (self) -> Self {
+        let mut token = self.grow();
+        token.value = Str(token.slice_source(self.source));
+        token
+    }
+    pub const fn grow_exp (self) -> Self {
+        let mut token = self.grow();
+        if let Exp(depth, _) = token.value {
+            token.value = Exp(depth, TokenIter::new(token.slice_source_exp(self.source)));
+        } else {
+            unreachable!()
+        }
+        token
+    }
+    pub const fn grow_in (self) -> Self {
+        let mut token = self.grow_exp();
+        if let Value::Exp(depth, source) = token.value {
+            token.value = Value::Exp(depth.saturating_add(1), source)
+        } else {
+            unreachable!()
+        }
+        token
+    }
+    pub const fn grow_out (self) -> Self {
+        let mut token = self.grow_exp();
+        if let Value::Exp(depth, source) = token.value {
+            if depth > 0 {
+                token.value = Value::Exp(depth - 1, source)
+            } else {
+                return self.error(Unexpected(')'))
+            }
+        } else {
+            unreachable!()
+        }
+        token
+    }
+}
diff --git a/dsl/src/lib.rs b/dsl/src/lib.rs
index c685572..411974a 100644
--- a/dsl/src/lib.rs
+++ b/dsl/src/lib.rs
@@ -1,36 +1,3 @@
-//! [Token]s are parsed substrings with an associated [Value].
-//!
-//! * [ ] FIXME: Value may be [Err] which may shadow [Result::Err]
-//! * [Value::Exp] wraps an expression depth and a [SourceIter]
-//!   with the remaining part of the expression.
-//!   * expression depth other that 0 mean unclosed parenthesis.
-//!   * closing and unopened parenthesis panics during reading.
-//!   * [ ] TODO: signed depth might be interesting
-//! * [Value::Sym] and [Value::Key] are stringish literals
-//!   with slightly different parsing rules.
-//! * [Value::Num] is an unsigned integer literal.
-//!```
-//! use tengri_dsl::{*, Value::*};
-//! let source = include_str!("../test.edn");
-//! let mut view = TokenIter::new(source);
-//! assert_eq!(view.peek(), Some(Token {
-//!     source,
-//!     start: 0,
-//!     length: source.len(),
-//!     value: Exp(0, TokenIter::new(&source[1..]))
-//! }));
-//!```
-//! The token iterator [TokenIter] allows you to get the
-//! general-purpose syntactic [Token]s represented by the source text.
-//!
-//! Both iterators are `peek`able:
-//!
-//! ```
-//! let src = include_str!("../test.edn");
-//! let mut view = tengri_dsl::TokenIter::new(src);
-//! assert_eq!(view.0.0, src);
-//! assert_eq!(view.peek(), view.0.peek())
-//! ```
 #![feature(adt_const_params)]
 #![feature(type_alias_impl_trait)]
 #![feature(impl_trait_in_fn_trait_return)]
@@ -41,7 +8,11 @@ pub(crate) use konst::iter::{ConstIntoIter, IsIteratorKind};
 pub(crate) use konst::string::{split_at, str_range, char_indices};
 pub(crate) use std::fmt::Debug;
 
-mod dsl; pub use self::dsl::*;
+mod dsl_error;   pub use self::dsl_error::*;
+mod dsl_token;   pub use self::dsl_token::*;
+mod dsl_iter;    pub use self::dsl_iter::*;
+mod dsl_context; pub use self::dsl_context::*;
+mod dsl_macros;
 
 #[cfg(test)] mod test_token_iter {
     use crate::*;
@@ -143,6 +114,22 @@ mod dsl; pub use self::dsl::*;
     Ok(())
 }
 
+#[cfg(test)] #[test] fn test_dsl_context () {
+    struct Test;
+    #[tengri_proc::expose]
+    impl Test {
+        fn some_bool (&self) -> bool {
+            true
+        }
+    }
+    assert_eq!(Test.get(&Value::Sym(":false")),        Some(false));
+    assert_eq!(Test.get(&Value::Sym(":true")),         Some(true));
+    assert_eq!(Test.get(&Value::Sym(":some-bool")),    Some(true));
+    assert_eq!(Test.get(&Value::Sym(":missing-bool")), None);
+    assert_eq!(Test.get(&Value::Num(0)), Some(false));
+    assert_eq!(Test.get(&Value::Num(1)), Some(true));
+}
+
 //#[cfg(test)] #[test] fn test_examples () -> Result<(), ParseError> {
     //// Let's pretend to render some view.
     //let source = include_str!("../../tek/src/view_arranger.edn");
diff --git a/input/src/input_dsl.rs b/input/src/input_dsl.rs
index cde5a15..bb5346d 100644
--- a/input/src/input_dsl.rs
+++ b/input/src/input_dsl.rs
@@ -29,7 +29,7 @@ impl<'state, S, C: DslCommand<'state, S>, I: DslInput> KeyMap<'state, S, C, I> f
                     match exp_iter.next() {
                         Some(Token { value: Value::Sym(binding), .. }) => {
                             if input.matches_dsl(binding) {
-                                if let Some(command) = C::try_from_expr(state, &mut exp_iter) {
+                                if let Some(command) = C::try_from_expr(state, exp_iter.clone()) {
                                     return Some(command)
                                 }
                             }
@@ -55,7 +55,7 @@ impl<'state, S, C: DslCommand<'state, S>, I: DslInput> KeyMap<'state, S, C, I> f
                     match exp_iter.next() {
                         Some(Token { value: Value::Sym(binding), .. }) => {
                             if input.matches_dsl(binding) {
-                                if let Some(command) = C::try_from_expr(state, &mut exp_iter) {
+                                if let Some(command) = C::try_from_expr(state, exp_iter.clone()) {
                                     return Some(command)
                                 }
                             }
@@ -132,7 +132,8 @@ where
     M: KeyMap<'state, S, C, I> + Send + Sync
 {
     fn fmt (&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        write!(f, "[InputMap: {} layer(s)]", self.layers.len())
+        write!(f, "[InputMap: {} layer(s)]", self.layers.len());
+        Ok(())
     }
 }
 
diff --git a/input/src/input_handle.rs b/input/src/input_handle.rs
index 99bce29..2a8fbcb 100644
--- a/input/src/input_handle.rs
+++ b/input/src/input_handle.rs
@@ -18,17 +18,15 @@ pub trait Input: Send + Sync + Sized {
 /// Implement the [Handle] trait.
 #[macro_export] macro_rules! handle {
     (|$self:ident:$Struct:ty,$input:ident|$handler:expr) => {
-        impl<E: Engine> ::tengri::input::Handle<E> for $Struct {
+        impl<E: Engine> Handle<E> for $Struct {
             fn handle (&mut $self, $input: &E) -> Perhaps<E::Handled> {
                 $handler
             }
         }
     };
     ($E:ty: |$self:ident:$Struct:ty,$input:ident|$handler:expr) => {
-        impl ::tengri::input::Handle<$E> for $Struct {
-            fn handle (&mut $self, $input: &$E) ->
-                Perhaps<<$E as ::tengri::input::Input>::Handled>
-            {
+        impl Handle<$E> for $Struct {
+            fn handle (&mut $self, $input: &$E) -> Perhaps<<$E as Input>::Handled> {
                 $handler
             }
         }
diff --git a/output/src/lib.rs b/output/src/lib.rs
index 45bf90a..064d8da 100644
--- a/output/src/lib.rs
+++ b/output/src/lib.rs
@@ -64,6 +64,7 @@ pub type Perhaps<T> = Result<Option<T>, Box<dyn Error>>;
 #[cfg(test)] mod test {
     use crate::*;
     use proptest::{prelude::*, option::of};
+    use proptest::option::of;
 
     proptest! {
         #[test] fn proptest_direction (
diff --git a/output/src/ops/bsp.rs b/output/src/ops/bsp.rs
index fe48efc..0ab80c3 100644
--- a/output/src/ops/bsp.rs
+++ b/output/src/ops/bsp.rs
@@ -1,11 +1,7 @@
 use crate::*;
 pub use Direction::*;
 /// A split or layer.
-pub struct Bsp<A, B>(
-    pub(crate) Direction,
-    pub(crate) A,
-    pub(crate) B,
-);
+pub struct Bsp<X, Y>(Direction, X, Y);
 impl<E: Output, A: Content<E>, B: Content<E>> Content<E> for Bsp<A, B> {
     fn layout (&self, outer: E::Area) -> E::Area {
         let [_, _, c] = self.areas(outer);
diff --git a/output/src/ops/cond.rs b/output/src/ops/cond.rs
index 5e71bef..521fdf8 100644
--- a/output/src/ops/cond.rs
+++ b/output/src/ops/cond.rs
@@ -22,13 +22,18 @@ impl<A, B> Either<A, B> {
 try_from_expr!(<'source, 'state, E>: When<RenderBox<'state, E>>: |state, iter| {
     if let Some(Token { value: Value::Key("when"), .. }) = iter.peek() {
         let _ = iter.next().unwrap();
-        let content = iter.next().expect("no content specified").value;
-        return Some(Self(
-            state.get(&mut iter)
-                .expect("no condition provided"),
-            state.get_content(&content)
-                .unwrap_or_else(||panic!("no content corresponding to for {:?}", &content))
-        ))
+
+        let condition = iter.next().expect("no condition specified");
+        let condition = state.get(&mut iter).expect("no condition provided");
+
+        let content = iter.next().expect("no content specified");
+        let content = if let Some(content) = state.get_content(&content.value) {
+            content
+        } else {
+            panic!("no content corresponding to for {:?}", &content);
+        };
+
+        return Some(Self(condition, content))
     }
 });
 
@@ -36,16 +41,25 @@ try_from_expr!(<'source, 'state, E>: When<RenderBox<'state, E>>: |state, iter| {
 try_from_expr!(<'source, 'state, E>: Either<RenderBox<'state, E>, RenderBox<'state, E>>: |state, iter| {
     if let Some(Token { value: Value::Key("either"), .. }) = iter.peek() {
         let _ = iter.next().unwrap();
-        let content   = iter.next().expect("no content specified").value;
-        let alternate = iter.next().expect("no alternate specified").value;
-        return Some(Self(
-            state.get(&mut iter)
-                .expect("no condition provided"),
-            state.get_content(&content)
-                .unwrap_or_else(||panic!("no content 1 corresponding to {:?}", &content)),
-            state.get_content(&alternate)
-                .unwrap_or_else(||panic!("no content 2 corresponding to {:?}", &alternate)),
-        ))
+
+        let condition = iter.next().expect("no condition specified");
+        let condition = state.get(&mut iter).expect("no condition provided");
+
+        let content = iter.next().expect("no content specified");
+        let content = if let Some(content) = state.get_content(&content.value) {
+            content
+        } else {
+            panic!("no content 1 corresponding to {:?}", &content);
+        };
+
+        let alternate = iter.next().expect("no alternate specified");
+        let alternate = if let Some(alternate) = state.get_content(&alternate.value) {
+            alternate
+        } else {
+            panic!("no content 2 corresponding to {:?}", &alternate);
+        };
+
+        return Some(Self(condition, content, alternate))
     }
 });
 
diff --git a/output/src/ops/transform.rs b/output/src/ops/transform.rs
index 904eba4..0dd2264 100644
--- a/output/src/ops/transform.rs
+++ b/output/src/ops/transform.rs
@@ -35,7 +35,7 @@ macro_rules! transform_xy {
         #[cfg(feature = "dsl")]
         impl<'state, E: Output + 'state, T: ViewContext<'state, E>> TryFromDsl<'state, T>
         for $Enum<RenderBox<'state, E>> {
-            fn try_from_expr <'source: 'state> (state: &'state T, iter: &mut TokenIter<'source>)
+            fn try_from_expr <'source: 'state> (state: &'state T, iter: TokenIter<'source>)
                 -> Option<Self>
             {
                 let mut iter = iter.clone();
@@ -43,11 +43,7 @@ macro_rules! transform_xy {
                     if k == $x || k == $y || k == $xy {
                         let _ = iter.next().unwrap();
                         let token = iter.next().expect("no content specified");
-                        let content = if let Some(content) = state.get_content(&token.value) {
-                            content
-                        } else {
-                            panic!("no content corresponding to {:?}", &token.value);
-                        };
+                        let content = get_content!(state => token);
                         return Some(match k {
                             $x => Self::x(content),
                             $y => Self::y(content),
@@ -88,7 +84,7 @@ macro_rules! transform_xy_unit {
         #[cfg(feature = "dsl")]
         impl<'state, E: Output + 'state, T: ViewContext<'state, E>> TryFromDsl<'state, T>
         for $Enum<E::Unit, RenderBox<'state, E>> {
-            fn try_from_expr <'source: 'state> (state: &'state T, iter: &mut TokenIter<'source>) -> Option<Self> {
+            fn try_from_expr <'source: 'state> (state: &'state T, iter: TokenIter<'source>) -> Option<Self> {
                 let mut iter = iter.clone();
                 if let Some(Token { value: Value::Key(k), .. }) = iter.peek() {
                     if k == $x || k == $y {
diff --git a/output/src/view.rs b/output/src/view.rs
index f2e9ef4..4bf3d73 100644
--- a/output/src/view.rs
+++ b/output/src/view.rs
@@ -103,7 +103,7 @@ pub trait ViewContext<'state, E: Output + 'state>: Send + Sync
         > TryFromDsl<$lt_state, T> for $Struct {
             fn try_from_expr <$lt_source: $lt_state> (
                 $state: &$lt_state T,
-                $iter: &mut TokenIter<$lt_source>
+                $iter: TokenIter<$lt_source>
             ) -> Option<Self> {
                 let mut $iter = $iter.clone();
                 $body;
diff --git a/proc/src/lib.rs b/proc/src/lib.rs
index 132d416..66dc0c7 100644
--- a/proc/src/lib.rs
+++ b/proc/src/lib.rs
@@ -2,17 +2,23 @@
 #![feature(box_patterns)]
 extern crate proc_macro;
 
-pub(crate) use std::collections::BTreeMap;
+pub(crate) use std::collections::{BTreeMap, BTreeSet};
 pub(crate) use std::cmp::Ordering;
 pub(crate) use std::sync::Arc;
 pub(crate) use proc_macro::TokenStream;
 pub(crate) use proc_macro2::{
-    TokenStream as TokenStream2, Ident, Span, Punct, Group, Delimiter, Spacing::*
+    TokenStream as TokenStream2, TokenTree,
+    Ident, Span, Punct, Spacing::*, Group, Delimiter, Literal
 };
 pub(crate) use syn::{
-    parse_macro_input, ImplItem, ImplItemFn, LitStr, Type,
-    ItemImpl, ReturnType, Signature, FnArg, Pat, PatType, PatIdent,
+    parse, parse_macro_input, parse_quote as pq,
+    braced, bracketed, parenthesized, Token,
+    Arm, Expr, Attribute, Meta, MetaList, Path, PathSegment, PathArguments,
+    ImplItem, ImplItemFn, LitStr, Type, ItemImpl, ReturnType, Signature, FnArg,
+    Pat, PatType, PatIdent,
     parse::{Parse, ParseStream, Result},
+    token::{PathSep, Brace},
+    punctuated::Punctuated,
 };
 pub(crate) use quote::{quote, TokenStreamExt, ToTokens};
 pub(crate) use heck::{AsKebabCase, AsUpperCamelCase};
@@ -21,7 +27,14 @@ mod proc_view;
 mod proc_expose;
 mod proc_command;
 
-#[cfg(test)] use syn::parse_quote as pq;
+#[proc_macro_attribute]
+pub fn view (meta: TokenStream, item: TokenStream) -> TokenStream {
+    use self::proc_view::{ViewDef, ViewMeta, ViewImpl};
+    write(ViewDef(
+        parse_macro_input!(meta as ViewMeta),
+        parse_macro_input!(item as ViewImpl),
+    ))
+}
 
 #[proc_macro_attribute]
 pub fn expose (meta: TokenStream, item: TokenStream) -> TokenStream {
@@ -41,15 +54,6 @@ pub fn command (meta: TokenStream, item: TokenStream) -> TokenStream {
     ))
 }
 
-#[proc_macro_attribute]
-pub fn view (meta: TokenStream, item: TokenStream) -> TokenStream {
-    use self::proc_view::{ViewDef, ViewMeta, ViewImpl};
-    write(ViewDef(
-        parse_macro_input!(meta as ViewMeta),
-        parse_macro_input!(item as ViewImpl),
-    ))
-}
-
 pub(crate) fn write <T: ToTokens> (t: T) -> TokenStream {
     let mut out = TokenStream2::new();
     t.to_tokens(&mut out);
@@ -69,175 +73,3 @@ pub(crate) fn write_quote_to (out: &mut TokenStream2, quote: TokenStream2) {
         out.append(token);
     }
 }
-
-#[cfg(test)] #[test] fn test_proc_view () {
-    let x: crate::proc_view::ViewMeta = pq! { SomeOutput };
-    let output: Ident = pq! { SomeOutput };
-    assert_eq!(x.output, output);
-
-    // TODO
-    let x: crate::proc_view::ViewImpl = pq! {
-        impl Foo {
-            /// docstring1
-            #[tengri::view(":view1")] #[bar] fn a_view () {}
-
-            #[baz]
-            /// docstring2
-            #[baz] fn is_not_view () {}
-        }
-    };
-    let expected_target: Ident = pq! { Foo };
-    //assert_eq!(x.target, expected_target);
-    //assert_eq!(x.items.len(), 2);
-    //assert_eq!(x.items[0].item, pq! {
-        ///// docstring1
-        //#[bar] fn a_view () {}
-    //});
-    //assert_eq!(x.items[1].item, pq! {
-        //#[baz]
-        ///// docstring2
-        //#[baz] fn is_not_view () {}
-    //});
-    //assert_eq!(x.syms, vec![
-        //ViewArm( { symbol: pq! { ":view1" }, name: pq! { a_view }, },
-    //]);
-    // FIXME
-    //let parsed: ViewDefinition = pq! {
-        //#[tengri_proc::view(SomeOutput)]
-        //impl SomeView {
-            //#[tengri::view(":view-1")]
-            //fn view_1 (&self) -> impl Content<SomeOutput> + use<'_> {
-                //"view-1"
-            //}
-        //}
-    //};
-    //let written = quote! { #parsed };
-    //assert_eq!(format!("{written}"), format!("{}", quote! {
-        //impl SomeView {
-            //fn view_1 (&self) -> impl Content<SomeOutput> + use<'_> {
-                //"view-1"
-            //}
-        //}
-        ///// Generated by [tengri_proc].
-        //impl ::tengri::output::Content<SomeOutput> for SomeView {
-            //fn content (&self) -> impl Render<SomeOutput> {
-                //self.size.of(::tengri::output::View(self, self.config.view))
-            //}
-        //}
-        ///// Generated by [tengri_proc].
-        //impl<'a> ::tengri::dsl::ViewContext<'a, SomeOutput> for SomeView {
-            //fn get_content_sym (&'a self, value: &Value<'a>) -> Option<RenderBox<'a, SomeOutput>> {
-                //match value {
-                    //::tengri::dsl::Value::Sym(":view-1") => self.view_1().boxed(),
-                    //_ => panic!("expected Sym(content), got: {value:?}")
-                //}
-            //}
-        //}
-    //}));
-}
-
-//#[cfg(test)] #[test] fn test_expose_definition () {
-    // TODO
-    //let parsed: ExposeImpl = pq! {
-        ////#[tengri_proc::expose]
-        //impl Something {
-            //fn something () -> bool {}
-        //}
-    //};
-    //// FIXME:
-    ////assert_eq!(
-        ////format!("{}", quote! { #parsed }),
-        ////format!("{}", quote! {
-            ////impl Something {
-                ////fn something () {}
-            ////}
-            ////impl ::tengri::Context<bool> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Sym(":true")  => true,
-                        ////::tengri::Value::Sym(":false") => false,
-                        ////::tengri::Value::Sym(":bool1") => true || false,
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-        ////})
-    ////);
-
-    //let parsed: ExposeImpl = pq! {
-        ////#[tengri_proc::expose]
-        //impl Something {
-            //#[tengri::expose(bool)] {
-                //":bool1" => true || false,
-            //}
-            //#[tengri::expose(u16)] {
-                //":u161" => 0 + 1,
-            //}
-            //#[tengri::expose(usize)] {
-                //":usize1" => 1 + 2,
-            //}
-            //#[tengri::expose(Arc<str>)] {
-                //":arcstr1" => "foo".into(),
-            //}
-            //#[tengri::expose(Option<Arc<str>>)] {
-                //":optarcstr1" => Some("bar".into()),
-                //":optarcstr2" => Some("baz".into()),
-            //}
-            //fn something () {}
-        //}
-    //};
-    //// FIXME:
-    ////assert_eq!(
-        ////format!("{}", quote! { #parsed }),
-        ////format!("{}", quote! {
-            ////impl Something {
-                ////fn something () {}
-            ////}
-            ////impl ::tengri::Context<Arc<str>> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<Arc<str>> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Sym(":arcstr1") => "foo".into(),
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-            ////impl ::tengri::Context<Option<Arc<str>>> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<Option<Arc<str>>> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Sym(":optarcstr1") => Some("bar".into()),
-                        ////::tengri::Value::Sym(":optarcstr2") => Some("baz".into()),
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-            ////impl ::tengri::Context<bool> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Sym(":true")  => true,
-                        ////::tengri::Value::Sym(":false") => false,
-                        ////::tengri::Value::Sym(":bool1") => true || false,
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-            ////impl ::tengri::Context<u16> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<u16> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Num(n) => *n as u16,
-                        ////::tengri::Value::Sym(":u161") => 0 + 1,
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-            ////impl ::tengri::Context<usize> for Something {
-                ////fn get (&self, dsl: &::tengri::Value) -> Option<usize> {
-                    ////Some(match dsl {
-                        ////::tengri::Value::Num(n) => *n as usize,
-                        ////::tengri::Value::Sym(":usize1") => 1 + 2,
-                        ////_ => return None
-                    ////})
-                ////}
-            ////}
-        ////})
-    ////)
-//}
diff --git a/proc/src/proc_command.rs b/proc/src/proc_command.rs
index cc5b134..456d797 100644
--- a/proc/src/proc_command.rs
+++ b/proc/src/proc_command.rs
@@ -68,9 +68,9 @@ impl ToTokens for CommandDef {
             }
             #block
             /// Generated by [tengri_proc].
-            impl<'state> ::tengri::dsl::TryFromDsl<'state, #target> for #enumeration {
+            impl<'state> TryFromDsl<'state, #target> for #enumeration {
                 fn try_from_expr <'source: 'state> (
-                    state: &'state #target, iter: &mut ::tengri::dsl::TokenIter<'source>
+                    state: &'state #target, iter: TokenIter<'source>
                 ) -> Option<Self> {
                     let mut iter = iter.clone();
                     match iter.next() {
@@ -80,15 +80,7 @@ impl ToTokens for CommandDef {
                 }
             }
             /// Generated by [tengri_proc].
-            impl<'state> ::tengri::dsl::Context<'state, #enumeration> for #target {
-                fn get <'source> (&self, iter: &mut ::tengri::dsl::TokenIter<'source>)
-                    -> Option<#enumeration>
-                {
-                    #enumeration::try_from_expr(self, iter)
-                }
-            }
-            /// Generated by [tengri_proc].
-            impl ::tengri::input::Command<#target> for #enumeration {
+            impl Command<#target> for #enumeration {
                 fn execute (self, state: &mut #target) -> Perhaps<Self> {
                     match self {
                         #(#implementations)*
@@ -129,12 +121,13 @@ impl CommandArm {
             Some((arg, ty))
         } else {
             unreachable!("only typed args should be present at this position");
+            None
         })
     }
     fn to_enum_variant_def (&self) -> TokenStream2 {
         let mut out = TokenStream2::new();
         out.append(self.to_enum_variant_ident());
-        //let ident = &self.0;
+        let ident = &self.0;
         if self.has_args() {
             out.append(Group::new(Delimiter::Brace, {
                 let mut out = TokenStream2::new();
@@ -155,12 +148,12 @@ impl CommandArm {
             out.append(Group::new(Delimiter::Brace, {
                 let mut out = TokenStream2::new();
                 for (arg, ty) in self.args() {
-                    //let take_err = LitStr::new(&format!("{}: missing argument \"{}\" ({})",
-                        //quote!{#ident}, quote!{#arg}, quote!{#ty}), Span::call_site());
+                    let take_err = LitStr::new(&format!("{}: missing argument \"{}\" ({})",
+                        quote!{#ident}, quote!{#arg}, quote!{#ty}), Span::call_site());
                     let give_err = LitStr::new(&format!("{}: missing value for \"{}\" ({})",
                         quote!{#ident}, quote!{#arg}, quote!{#ty}), Span::call_site());
                     write_quote_to(&mut out, quote! {
-                        #arg: ::tengri::dsl::Context::get(state, &mut iter).expect(#give_err),
+                        #arg: Context::get(state, &mut iter).expect(#give_err),
                     });
                 }
                 out
@@ -171,11 +164,11 @@ impl CommandArm {
     fn to_enum_variant_unbind (&self) -> TokenStream2 {
         let mut out = TokenStream2::new();
         out.append(self.to_enum_variant_ident());
-        //let ident = &self.0;
+        let ident = &self.0;
         if self.has_args() {
             out.append(Group::new(Delimiter::Brace, {
                 let mut out = TokenStream2::new();
-                for (arg, _ty) in self.args() {
+                for (arg, ty) in self.args() {
                     write_quote_to(&mut out, quote! { #arg , });
                 }
                 out
@@ -196,10 +189,8 @@ impl CommandArm {
     fn to_implementation (&self) -> TokenStream2 {
         let ident = &self.0;
         let variant = self.to_enum_variant_unbind();
-        let give_rest = write_quote(quote! { /*TODO*/ });
-        let give_args = self.args()
-            .map(|(arg, _ty)|write_quote(quote! { #arg, }))
-            .collect::<Vec<_>>();
+        let mut give_rest = write_quote(quote! { /*TODO*/ });
+        let give_args = self.args().map(|(arg, ty)|write_quote(quote! { #arg, })).collect::<Vec<_>>();
         write_quote(quote! { Self::#variant => Self::#ident(state, #(#give_args)* #give_rest), })
     }
 }
@@ -225,3 +216,35 @@ impl ToTokens for CommandVariant {
         out.append(Punct::new(',', Alone));
     }
 }
+
+impl ToTokens for CommandArm {
+    fn to_tokens (&self, out: &mut TokenStream2) {
+        let Self(ident, args, returnType) = self;
+        for ident in ["tengri", "dsl", "Value", "Sym"].iter() {
+            out.append(Punct::new(':', Joint));
+            out.append(Punct::new(':', Alone));
+            out.append(Ident::new(ident, Span::call_site()));
+        }
+        out.append(Group::new(Delimiter::Parenthesis, {
+            let mut out = TokenStream2::new();
+            out.append(self.to_enum_variant_ident());
+            out
+        }));
+        out.append(Punct::new('=', Joint));
+        out.append(Punct::new('>', Alone));
+        out.append(Ident::new("Self", Span::call_site()));
+        out.append(Punct::new(':', Joint));
+        out.append(Punct::new(':', Alone));
+        out.append(ident.clone());
+        out.append(Group::new(Delimiter::Parenthesis, {
+            let mut out = TokenStream2::new();
+            for arg in args.iter() {
+                // TODO
+                out.append(LitStr::new(&self.to_key(), Span::call_site()).token());
+                out.append(Punct::new(',', Alone));
+            }
+            out
+        }));
+        out.append(Punct::new(',', Alone));
+    }
+}
diff --git a/proc/src/proc_expose.rs b/proc/src/proc_expose.rs
index 4a11347..15e08e8 100644
--- a/proc/src/proc_expose.rs
+++ b/proc/src/proc_expose.rs
@@ -19,7 +19,7 @@ struct ExposeSym(LitStr);
 struct ExposeType(Box<Type>);
 
 impl Parse for ExposeMeta {
-    fn parse (_input: ParseStream) -> Result<Self> {
+    fn parse (input: ParseStream) -> Result<Self> {
         Ok(Self)
     }
 }
@@ -189,3 +189,109 @@ impl ToTokens for ExposeType {
         self.0.to_tokens(out)
     }
 }
+
+#[cfg(test)] #[test] fn test_expose_definition () {
+    // TODO
+    //let parsed: ExposeImpl = pq! {
+        ////#[tengri_proc::expose]
+        //impl Something {
+            //fn something () -> bool {}
+        //}
+    //};
+    //// FIXME:
+    ////assert_eq!(
+        ////format!("{}", quote! { #parsed }),
+        ////format!("{}", quote! {
+            ////impl Something {
+                ////fn something () {}
+            ////}
+            ////impl ::tengri::Context<bool> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":true")  => true,
+                        ////::tengri::Value::Sym(":false") => false,
+                        ////::tengri::Value::Sym(":bool1") => true || false,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+        ////})
+    ////);
+
+    //let parsed: ExposeImpl = pq! {
+        ////#[tengri_proc::expose]
+        //impl Something {
+            //#[tengri::expose(bool)] {
+                //":bool1" => true || false,
+            //}
+            //#[tengri::expose(u16)] {
+                //":u161" => 0 + 1,
+            //}
+            //#[tengri::expose(usize)] {
+                //":usize1" => 1 + 2,
+            //}
+            //#[tengri::expose(Arc<str>)] {
+                //":arcstr1" => "foo".into(),
+            //}
+            //#[tengri::expose(Option<Arc<str>>)] {
+                //":optarcstr1" => Some("bar".into()),
+                //":optarcstr2" => Some("baz".into()),
+            //}
+            //fn something () {}
+        //}
+    //};
+    //// FIXME:
+    ////assert_eq!(
+        ////format!("{}", quote! { #parsed }),
+        ////format!("{}", quote! {
+            ////impl Something {
+                ////fn something () {}
+            ////}
+            ////impl ::tengri::Context<Arc<str>> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<Arc<str>> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":arcstr1") => "foo".into(),
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<Option<Arc<str>>> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<Option<Arc<str>>> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":optarcstr1") => Some("bar".into()),
+                        ////::tengri::Value::Sym(":optarcstr2") => Some("baz".into()),
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<bool> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":true")  => true,
+                        ////::tengri::Value::Sym(":false") => false,
+                        ////::tengri::Value::Sym(":bool1") => true || false,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<u16> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<u16> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Num(n) => *n as u16,
+                        ////::tengri::Value::Sym(":u161") => 0 + 1,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<usize> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<usize> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Num(n) => *n as usize,
+                        ////::tengri::Value::Sym(":usize1") => 1 + 2,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+        ////})
+    ////)
+}
diff --git a/proc/src/proc_view.rs b/proc/src/proc_view.rs
index 7fdd1fd..b62d976 100644
--- a/proc/src/proc_view.rs
+++ b/proc/src/proc_view.rs
@@ -5,7 +5,7 @@ pub(crate) struct ViewDef(pub(crate) ViewMeta, pub(crate) ViewImpl);
 
 #[derive(Debug, Clone)]
 pub(crate) struct ViewMeta {
-    pub(crate) output: Ident,
+    output: Ident,
 }
 
 #[derive(Debug, Clone)]
@@ -45,16 +45,7 @@ impl ToTokens for ViewDef {
     fn to_tokens (&self, out: &mut TokenStream2) {
         let Self(ViewMeta { output }, ViewImpl { block, exposed }) = self;
         let ident = &block.self_ty;
-        let mut available = vec![];
-        let exposed: Vec<_> = exposed.iter().map(|(k,v)|{
-            available.push(k.clone());
-            ViewArm(k.clone(), v.clone())
-        }).collect();
-        let available: String = available.join(", ");
-        let error_msg = LitStr::new(
-            &format!("expected Sym(content), got: {{value:?}}, available: {available}"),
-            Span::call_site()
-        );
+        let exposed: Vec<_> = exposed.iter().map(|(k,v)|ViewArm(k.clone(), v.clone())).collect();
         for token in quote! {
             #block
             /// Generated by [tengri_proc].
@@ -68,7 +59,10 @@ impl ToTokens for ViewDef {
                 fn get_content_sym <'source: 'state> (&'state self, value: &Value<'source>)
                     -> Option<RenderBox<'state, #output>>
                 {
-                    match value { #(#exposed)* _ => panic!(#error_msg) }
+                    match value {
+                        #(#exposed)*
+                        _ => panic!("expected Sym(content), got: {value:?}")
+                    }
                 }
             }
         } {
@@ -114,3 +108,132 @@ impl ToTokens for ViewArm {
         out.append(Punct::new(',', Alone));
     }
 }
+
+//impl ToTokens for ViewSym {
+    //fn to_tokens (&self, out: &mut TokenStream2) {
+        //out.append(Punct::new(':', Joint));
+        //out.append(Punct::new(':', Alone));
+        //out.append(Ident::new("tengri", Span::call_site()));
+        //out.append(Punct::new(':', Joint));
+        //out.append(Punct::new(':', Alone));
+        //out.append(Ident::new("dsl", Span::call_site()));
+        //out.append(Punct::new(':', Joint));
+        //out.append(Punct::new(':', Alone));
+        //out.append(Ident::new("Value", Span::call_site()));
+        //out.append(Punct::new(':', Joint));
+        //out.append(Punct::new(':', Alone));
+        //out.append(Ident::new("Sym", Span::call_site()));
+        //out.append(Group::new(Delimiter::Parenthesis, {
+            //let mut out = TokenStream2::new();
+            //out.append(self.symbol.clone());
+            //out
+        //}));
+        //out.append(Punct::new('=', Joint));
+        //out.append(Punct::new('>', Alone));
+        //out.append(Ident::new("Some", Span::call_site()));
+        //out.append(Group::new(Delimiter::Parenthesis, {
+            //let mut out = TokenStream2::new();
+            //out.append(Ident::new("self", Span::call_site()));
+            //out.append(Punct::new('.', Alone));
+            //out.append(self.name.clone());
+            //out.append(Group::new(Delimiter::Parenthesis, TokenStream2::new()));
+            //out.append(Punct::new('.', Alone));
+            //out.append(Ident::new("boxed", Span::call_site()));
+            //out.append(Group::new(Delimiter::Parenthesis, TokenStream2::new()));
+            //out
+        //}));
+        //out.append(Punct::new(',', Alone));
+    //}
+//}
+
+fn nth_segment_is (segments: &Punctuated<PathSegment, PathSep>, n: usize, x: &str) -> bool {
+    if let Some(PathSegment { arguments: PathArguments::None, ident, .. }) = segments.get(n) {
+        if format!("{ident}") == x {
+            return true
+        }
+    }
+    return false
+}
+
+//impl std::cmp::PartialEq for ViewItem {
+    //fn eq (&self, other: &Self) -> bool {
+        //self.item == other.item && (format!("{:?}", self.expose) == format!("{:?}", other.expose))
+    //}
+//}
+
+//impl std::cmp::PartialEq for ViewSym {
+    //fn eq (&self, other: &Self) -> bool {
+        //self.name == other.name && (format!("{}", self.symbol) == format!("{}", other.symbol))
+    //}
+//}
+
+#[cfg(test)] #[test] fn test_view_meta () {
+    let x: ViewMeta   = pq! { SomeOutput };
+    let output: Ident = pq! { SomeOutput };
+    assert_eq!(x.output, output);
+}
+
+#[cfg(test)] #[test] fn test_view_impl () {
+    // TODO
+    let x: ViewImpl = pq! {
+        impl Foo {
+            /// docstring1
+            #[tengri::view(":view1")] #[bar] fn a_view () {}
+
+            #[baz]
+            /// docstring2
+            #[baz] fn is_not_view () {}
+        }
+    };
+    let expected_target: Ident = pq! { Foo };
+    //assert_eq!(x.target, expected_target);
+    //assert_eq!(x.items.len(), 2);
+    //assert_eq!(x.items[0].item, pq! {
+        ///// docstring1
+        //#[bar] fn a_view () {}
+    //});
+    //assert_eq!(x.items[1].item, pq! {
+        //#[baz]
+        ///// docstring2
+        //#[baz] fn is_not_view () {}
+    //});
+    //assert_eq!(x.syms, vec![
+        //ViewArm( { symbol: pq! { ":view1" }, name: pq! { a_view }, },
+    //]);
+}
+
+#[cfg(test)] #[test] fn test_view_definition () {
+    // FIXME
+    //let parsed: ViewDefinition = pq! {
+        //#[tengri_proc::view(SomeOutput)]
+        //impl SomeView {
+            //#[tengri::view(":view-1")]
+            //fn view_1 (&self) -> impl Content<SomeOutput> + use<'_> {
+                //"view-1"
+            //}
+        //}
+    //};
+    //let written = quote! { #parsed };
+    //assert_eq!(format!("{written}"), format!("{}", quote! {
+        //impl SomeView {
+            //fn view_1 (&self) -> impl Content<SomeOutput> + use<'_> {
+                //"view-1"
+            //}
+        //}
+        ///// Generated by [tengri_proc].
+        //impl ::tengri::output::Content<SomeOutput> for SomeView {
+            //fn content (&self) -> impl Render<SomeOutput> {
+                //self.size.of(::tengri::output::View(self, self.config.view))
+            //}
+        //}
+        ///// Generated by [tengri_proc].
+        //impl<'a> ::tengri::dsl::ViewContext<'a, SomeOutput> for SomeView {
+            //fn get_content_sym (&'a self, value: &Value<'a>) -> Option<RenderBox<'a, SomeOutput>> {
+                //match value {
+                    //::tengri::dsl::Value::Sym(":view-1") => self.view_1().boxed(),
+                    //_ => panic!("expected Sym(content), got: {value:?}")
+                //}
+            //}
+        //}
+    //}));
+}
diff --git a/tengri/Cargo.toml b/tengri/Cargo.toml
index 23e87f8..1c7d4eb 100644
--- a/tengri/Cargo.toml
+++ b/tengri/Cargo.toml
@@ -10,11 +10,6 @@ tengri_input  = { optional = true, path = "../input"  }
 tengri_output = { optional = true, path = "../output" }
 tengri_tui    = { optional = true, path = "../tui"    }
 
-[dev-dependencies]
-tengri_proc = { path = "../proc" }
-tengri      = { path = ".", features = [ "dsl" ] }
-crossterm   = "0.28.1"
-
 [features]
 default = [ "input", "output", "tui" ]
 input   = [ "tengri_input" ]
diff --git a/tengri/src/lib.rs b/tengri/src/lib.rs
index 53850cd..c1c72a0 100644
--- a/tengri/src/lib.rs
+++ b/tengri/src/lib.rs
@@ -2,98 +2,3 @@
 #[cfg(feature="input")]  pub use ::tengri_input  as input;
 #[cfg(feature="dsl")]    pub use ::tengri_dsl    as dsl;
 #[cfg(feature="tui")]    pub use ::tengri_tui    as tui;
-
-#[cfg(test)] extern crate tengri_proc;
-#[cfg(test)] #[test] fn test_subcommand () -> crate::output::Usually<()> {
-    use crate::output::Perhaps;
-    use crate::input::{Command, InputMap, KeyMap, Handle, handle};
-    use crate::dsl::{TryFromDsl, TokenIter};
-    use crate::tui::TuiIn;
-    use crossterm::event::{Event, KeyEvent, KeyCode, KeyModifiers, KeyEventKind, KeyEventState};
-    //use crate::input::*;
-    //use crate::dsl::*;
-    struct Test {
-        keys: InputMap<'static, Test, TestCommand, TuiIn, TokenIter<'static>>
-    }
-    handle!(TuiIn: |self: Test, input|if let Some(command) = self.keys.command(self, input) {
-        Ok(Some(true))
-    } else {
-        Ok(None)
-    });
-    #[tengri_proc::command(Test)] impl TestCommand {
-        fn do_thing (state: &mut Test) -> Perhaps<Self> {
-            Ok(None)
-        }
-        fn do_thing_arg (state: &mut Test, arg: usize) -> Perhaps<Self> {
-            Ok(None)
-        }
-        fn do_sub (state: &mut Test, command: TestSubcommand) -> Perhaps<Self> {
-            Ok(command.execute(state)?.map(|command|Self::DoSub { command }))
-        }
-    }
-    #[tengri_proc::command(Test)] impl TestSubcommand {
-        fn do_other_thing (state: &mut Test) -> Perhaps<Self> {
-            Ok(None)
-        }
-        fn do_other_thing_arg (state: &mut Test, arg: usize) -> Perhaps<Self> {
-            Ok(None)
-        }
-    }
-    let mut test = Test {
-        keys: InputMap::new("
-            (@a do-thing)
-            (@b do-thing-arg 0)
-            (@c do-sub do-other-thing)
-            (@d do-sub do-other-thing-arg 0)
-        ".into())
-    };
-    assert_eq!(Some(true), test.handle(&TuiIn(Default::default(), Event::Key(KeyEvent {
-        kind:      KeyEventKind::Press,
-        code:      KeyCode::Char('a'),
-        modifiers: KeyModifiers::NONE,
-        state:     KeyEventState::NONE,
-    })))?);
-    assert_eq!(Some(true), test.handle(&TuiIn(Default::default(), Event::Key(KeyEvent {
-        kind:      KeyEventKind::Press,
-        code:      KeyCode::Char('b'),
-        modifiers: KeyModifiers::NONE,
-        state:     KeyEventState::NONE,
-    })))?);
-    assert_eq!(Some(true), test.handle(&TuiIn(Default::default(), Event::Key(KeyEvent {
-        kind:      KeyEventKind::Press,
-        code:      KeyCode::Char('c'),
-        modifiers: KeyModifiers::NONE,
-        state:     KeyEventState::NONE,
-    })))?);
-    assert_eq!(Some(true), test.handle(&TuiIn(Default::default(), Event::Key(KeyEvent {
-        kind:      KeyEventKind::Press,
-        code:      KeyCode::Char('d'),
-        modifiers: KeyModifiers::NONE,
-        state:     KeyEventState::NONE,
-    })))?);
-    assert_eq!(None, test.handle(&TuiIn(Default::default(), Event::Key(KeyEvent {
-        kind:      KeyEventKind::Press,
-        code:      KeyCode::Char('z'),
-        modifiers: KeyModifiers::NONE,
-        state:     KeyEventState::NONE,
-    })))?);
-    Ok(())
-}
-
-#[cfg(test)] #[test] fn test_dsl_context () {
-    use crate::dsl::Value;
-
-    struct Test;
-    #[tengri_proc::expose]
-    impl Test {
-        fn some_bool (&self) -> bool {
-            true
-        }
-    }
-    assert_eq!(Test.get(&Value::Sym(":false")),        Some(false));
-    assert_eq!(Test.get(&Value::Sym(":true")),         Some(true));
-    assert_eq!(Test.get(&Value::Sym(":some-bool")),    Some(true));
-    assert_eq!(Test.get(&Value::Sym(":missing-bool")), None);
-    assert_eq!(Test.get(&Value::Num(0)), Some(false));
-    assert_eq!(Test.get(&Value::Num(1)), Some(true));
-}
diff --git a/tui/examples/tui.rs b/tui/examples/tui.rs
index 0d3ef75..3869a8e 100644
--- a/tui/examples/tui.rs
+++ b/tui/examples/tui.rs
@@ -43,9 +43,6 @@ handle!(TuiIn: |self: Example, input|{
 
 #[tengri_proc::expose]
 impl Example {
-    fn _todo_u16_stub (&self) -> u16 { todo!() }
-    fn _todo_bool_stub (&self) -> bool { todo!() }
-    fn _todo_usize_stub (&self) -> usize { todo!() }
     //[bool]  => {}
     //[u16]   => {}
     //[usize] => {}