diff --git a/dsl/README.md b/dsl/README.md
index 97f1d2c..a5bcf22 100644
--- a/dsl/README.md
+++ b/dsl/README.md
@@ -92,3 +92,24 @@ or configuration statements, and look like this:
 * [ ] const parse
 * [ ] live reload
 * [ ] serialize modified code back to original indentation
+
+## implementation notes
+
+### `DslExp` trait behavior
+
+this is the trait which differentiates "a thing" from
+"a thing that is many things".
+
+|source         |key|exp    |head     |tail           |
+|---------------|---|-------|---------|---------------|
+|`a`            |`a`|e0     |`a`      |None           |
+|`(a)`          |e1 |`a`    |`(a)`    |None           |
+|`a b c`        |e2 |e0     |`a`      |`b c`          |
+|`(a b c)`      |e1 |`a b c`|`(a b c)`|               |
+|`(a b c) d e`  |e1 |e3     |`(a b c)`|`d e`          |
+|`a (b c d) e f`|e1 |e0     |`a`      |`(b c d) e f`  |
+
+* e0: Unexpected 'a'
+* e1: Unexpected '('
+* e2: Unexpected 'b'
+* e3: Unexpected 'd'
diff --git a/dsl/src/dsl.rs b/dsl/src/dsl.rs
index d8de0f5..c43e2f1 100644
--- a/dsl/src/dsl.rs
+++ b/dsl/src/dsl.rs
@@ -6,87 +6,45 @@
 extern crate const_panic;
 use const_panic::PanicFmt;
 use std::fmt::Debug;
-pub(crate) use std::error::Error;
-pub(crate) use std::sync::Arc;
-pub(crate) use konst::string::{str_range, char_indices};
+pub(crate) use std::{error::Error, sync::Arc};
+pub(crate) use konst::{iter::for_each, string::{str_from, str_range, char_indices}};
 pub(crate) use thiserror::Error;
 pub(crate) use ::tengri_core::*;
 pub(crate) use self::DslError::*;
 mod dsl_conv; pub use self::dsl_conv::*;
-mod dsl_parse;
-pub(crate) use self::dsl_parse::*;
-pub mod parse { pub use crate::dsl_parse::*; }
-
-#[cfg(test)]
-mod dsl_test;
-
+#[cfg(test)] mod dsl_test;
 flex_trait!(Dsl: Debug + Send + Sync + Sized {
-    fn src (&self) -> &str {
-        unreachable!("Dsl::src default impl")
-    }
+    fn src (&self) -> DslPerhaps<&str> { unreachable!("Dsl::src default impl") }
 });
-impl Dsl for Arc<str> {
-    fn src (&self) -> &str { self.as_ref() }
-}
-impl<'s> Dsl for &'s str {
-    fn src (&self) -> &str { self.as_ref() }
-}
+impl Dsl for Arc<str> { fn src (&self) -> DslPerhaps<&str> { Ok(Some(self.as_ref())) } }
+impl<'s> Dsl for &'s str { fn src (&self) -> DslPerhaps<&str> { Ok(Some(self.as_ref())) } }
 impl<D: Dsl> Dsl for Option<D> {
-    fn src (&self) -> &str { if let Some(dsl) = self { dsl.src() } else { "" } }
+    fn src (&self) -> DslPerhaps<&str> {Ok(if let Some(dsl) = self { dsl.src()? } else { None })}
 }
-
-impl<D: Dsl> DslExp for D {}
-pub trait DslExp: Dsl {
-    fn exp (&self) -> DslPerhaps<&str> {
-        Ok(exp_peek(self.src())?)
-    }
-    fn head (&self) -> DslPerhaps<&str> {
-        let start = 1;
-        let src   = self.src();
-        let src   = &src[start.min(src.len().saturating_sub(1))..];
-        peek(src)
-    }
-    fn tail (&self) -> DslPerhaps<&str> {
-        let start = 1;
-        let src   = self.src();
-        let src   = &src[start.min(src.len().saturating_sub(1))..];
-        Ok(if let Some((head_start, head_len)) = seek(src)? {
-            let start = 1 + head_start + head_len;
-            let src   = self.src();
-            let src   = &src[start.min(src.len().saturating_sub(1))..];
-            peek(src)?
-        } else {
-            None
-        })
-    }
+impl<D: Dsl> Dsl for Result<D, DslError> {
+    fn src (&self) -> DslPerhaps<&str> {match self {Ok(dsl) => Ok(dsl.src()?), Err(e) => Err(*e)}}
 }
-
-impl<D: Dsl> DslSym for D {}
-pub trait DslSym: Dsl {
-    fn sym (&self) -> DslPerhaps<&str> { crate::parse::sym_peek(self.src()) }
+impl<D: Dsl> DslExp for D {} pub trait DslExp: Dsl {
+    fn exp  (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(exp_peek_inner_only))}
+    fn head (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(peek))}
+    fn tail (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(peek_tail(self.head())))}
 }
-
-impl<D: Dsl> DslKey for D {}
-pub trait DslKey: Dsl {
-    fn key (&self) -> DslPerhaps<&str> { crate::parse::key_peek(self.src()) }
+impl<D: Dsl> DslText for D {} pub trait DslText: Dsl {
+    fn text (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(text_peek_only))}
 }
-
-impl<D: Dsl> DslText for D {}
-pub trait DslText: Dsl {
-    fn text (&self) -> DslPerhaps<&str> { crate::parse::text_peek(self.src()) }
+impl<D: Dsl> DslSym for D {} pub trait DslSym: Dsl {
+    fn sym  (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(sym_peek_only))}
 }
-
-impl<D: Dsl> DslNum for D {}
-pub trait DslNum: Dsl {
-    fn num (&self) -> DslPerhaps<&str> { crate::parse::num_peek(self.src()) }
+impl<D: Dsl> DslKey for D {} pub trait DslKey: Dsl {
+    fn key  (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(key_peek_only))}
+}
+impl<D: Dsl> DslNum for D {} pub trait DslNum: Dsl {
+    fn num  (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(num_peek_only))}
 }
-
 /// DSL-specific result type.
 pub type DslResult<T> = Result<T, DslError>;
-
 /// DSL-specific optional result type.
 pub type DslPerhaps<T> = Result<Option<T>, DslError>;
-
 /// DSL-specific error codes.
 #[derive(Error, Debug, Copy, Clone, PartialEq, PanicFmt)]
 pub enum DslError {
@@ -97,3 +55,245 @@ pub enum DslError {
     #[error("parse failed: error #{0}")] Code(u8),
     #[error("end reached")] End
 }
+#[macro_export] macro_rules! dsl_for_each (($dsl:expr => |$next:ident|$body:expr)=>{
+    let mut dsl:   Arc<str>         = $dsl.src().into();
+    let mut $next: Option<Arc<str>> = dsl.next()?.map(Into::into);
+    let mut rest:  Option<Arc<str>> = dsl.rest()?.map(Into::into);
+    loop {
+        if let Some($next) = $next { $body } else { break };
+        if let Some(next) = rest {
+            $next = next.next()?.map(Into::into);
+            rest  = next.rest()?.map(Into::into);
+        } else {
+            break
+        }
+    }
+});
+fn ok_flat <T> (x: Option<DslPerhaps<T>>) -> DslPerhaps<T> { Ok(x.transpose()?.flatten()) }
+fn peek_tail <'a> (head: DslPerhaps<&'a str>) -> impl Fn(&'a str)->DslPerhaps<&'a str> {
+    move|src|match head {
+        Ok(Some(next)) => {
+            let src = &src[src.len().min(1 + next.len())..];
+            for c in src.chars() { if !is_whitespace(c) { return Ok(Some(src)) } }
+            Ok(None)
+        },
+        e => e
+    }
+}
+macro_rules! def_peek_seek(($peek:ident, $peek_only:ident, $seek:ident, $seek_start:ident, $seek_length:ident)=>{
+    /// Find a slice corrensponding to a syntax token.
+    pub const fn $peek (source: &str) -> DslPerhaps<&str> {
+        match $seek(source) {
+            Err(e) => Err(e),
+            Ok(None) => Ok(None),
+            Ok(Some((start, length))) => Ok(Some(str_range(source, start, start + length))),
+        }
+    }
+    /// Find a slice corrensponding to a syntax token
+    /// but return an error if it isn't the only thing
+    /// in the source.
+    pub const fn $peek_only (source: &str) -> DslPerhaps<&str> {
+        match $seek(source) {
+            Err(e) => Err(e),
+            Ok(None) => Ok(None),
+            Ok(Some((start, length))) => {
+                if let Err(e) = no_trailing_non_whitespace(source, start + length) { return Err(e) }
+                Ok(Some(str_range(source, start, start + length)))
+            }
+        }
+    }
+    /// Find a start and length corresponding to a syntax token.
+    pub const fn $seek (source: &str) -> DslPerhaps<(usize, usize)> {
+        match $seek_start(source) {
+            Err(e) => Err(e),
+            Ok(None) => Ok(None),
+            Ok(Some(start)) => match $seek_length(str_from(source, start)) {
+                Ok(Some(length)) => Ok(Some((start, length))),
+                Ok(None) => Ok(None),
+                Err(e) => Err(e),
+            },
+        }
+    }
+});
+def_peek_seek!(exp_peek, exp_peek_only, exp_seek, exp_seek_start, exp_seek_length);
+pub const fn exp_peek_inner (source: &str) -> DslPerhaps<&str> {
+    match exp_peek(source) {
+        Ok(Some(peeked)) => {
+            let len = peeked.len();
+            let start = if len > 0 { 1 } else { 0 };
+            Ok(Some(str_range(source, start, start + len.saturating_sub(2))))
+        },
+        e => e
+    }
+}
+pub const fn exp_peek_inner_only (source: &str) -> DslPerhaps<&str> {
+    match exp_seek(source) {
+        Err(e) => Err(e),
+        Ok(None) => Ok(None),
+        Ok(Some((start, length))) => {
+            if let Err(e) = no_trailing_non_whitespace(source, start + length) { return Err(e) }
+            let peeked = str_range(source, start, start + length);
+            let len = peeked.len();
+            let start = if len > 0 { 1 } else { 0 };
+            Ok(Some(str_range(peeked, start, start + len.saturating_sub(2))))
+        },
+    }
+}
+pub const fn is_exp_start (c: char) -> bool { c == '(' }
+pub const fn is_exp_end (c: char) -> bool { c == ')' }
+pub const fn exp_seek_start (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_exp_start(c) {
+        return Ok(Some(i))
+    } else if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn exp_seek_length (source: &str) -> DslPerhaps<usize> {
+    let mut depth = 0;
+    for_each!((i, c) in char_indices(source) => if is_exp_start(c) {
+        depth += 1;
+    } else if is_exp_end(c) {
+        if depth == 0 {
+            return Err(Unexpected(c))
+        } else if depth == 1 {
+            return Ok(Some(i + 1))
+        } else {
+            depth -= 1;
+        }
+    });
+    Err(Incomplete)
+}
+def_peek_seek!(sym_peek, sym_peek_only, sym_seek, sym_seek_start, sym_seek_length);
+pub const fn is_sym_start (c: char) -> bool { matches!(c, ':'|'@') }
+pub const fn is_sym_char (c: char) -> bool { matches!(c, 'a'..='z'|'A'..='Z'|'0'..='9'|'-') }
+pub const fn is_sym_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
+pub const fn sym_seek_start (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_sym_start(c) {
+        return Ok(Some(i))
+    } else if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn sym_seek_length (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_sym_end(c) {
+        return Ok(Some(i))
+    } else if !is_sym_char(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(Some(source.len()))
+}
+def_peek_seek!(key_peek, key_peek_only, key_seek, key_seek_start, key_seek_length);
+pub const fn is_key_start (c: char) -> bool { matches!(c, '/'|('a'..='z')) }
+pub const fn is_key_char (c: char) -> bool { matches!(c, 'a'..='z'|'0'..='9'|'-'|'/') }
+pub const fn is_key_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
+pub const fn key_seek_start (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_key_start(c) {
+        return Ok(Some(i))
+    } else if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn key_seek_length (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_key_end(c) {
+        return Ok(Some(i))
+    } else if !is_key_char(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(Some(source.len()))
+}
+def_peek_seek!(text_peek, text_peek_only, text_seek, text_seek_start, text_seek_length);
+pub const fn is_text_start (c: char) -> bool { matches!(c, '"') }
+pub const fn is_text_end (c: char) -> bool { matches!(c, '"') }
+pub const fn text_seek_start (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_text_start(c) {
+        return Ok(Some(i))
+    } else if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn text_seek_length (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_text_end(c) { return Ok(Some(i)) });
+    Ok(None)
+}
+def_peek_seek!(num_peek, num_peek_only, num_seek, num_seek_start, num_seek_length);
+pub const fn num_seek_start (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_digit(c) {
+        return Ok(Some(i));
+    } else if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn num_seek_length (source: &str) -> DslPerhaps<usize> {
+    for_each!((i, c) in char_indices(source) => if is_num_end(c) {
+        return Ok(Some(i))
+    } else if !is_digit(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(None)
+}
+pub const fn is_digit (c: char) -> bool { matches!(c, '0'..='9') }
+pub const fn is_num_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
+pub const fn to_number <D: Dsl> (digits: &str) -> Result<usize, DslError> {
+    let mut iter = char_indices(digits);
+    let mut value = 0;
+    while let Some(((_, c), next)) = iter.next() {
+        match to_digit(c) {
+            Ok(digit) => value = 10 * value + digit,
+            Err(e) => return Err(e),
+        }
+        iter = next;
+    }
+    Ok(value)
+}
+pub const fn to_digit (c: char) -> Result<usize, DslError> {
+    Ok(match c {
+        '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
+        '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9,
+        _ => return Err(Unexpected(c))
+    })
+}
+pub const fn peek (src: &str) -> DslPerhaps<&str> {
+    Ok(Some(match () {
+        _ if let Ok(Some(exp))  = exp_peek(src) => exp,
+        _ if let Ok(Some(sym))  = sym_peek(src) => sym,
+        _ if let Ok(Some(key))  = key_peek(src) => key,
+        _ if let Ok(Some(num))  = num_peek(src) => num,
+        _ if let Ok(Some(text)) = text_peek(src) => text,
+        _ => {
+            for_each!((_, c) in char_indices(src) => if !is_whitespace(c) {
+                return Err(Unexpected(c))
+            });
+            return Ok(None)
+        }
+    }))
+}
+pub const fn seek (src: &str) -> DslPerhaps<(usize, usize)> {
+    Ok(Some(match () {
+        _ if let Ok(Some(exp))  = exp_seek(src) => exp,
+        _ if let Ok(Some(sym))  = sym_seek(src) => sym,
+        _ if let Ok(Some(key))  = key_seek(src) => key,
+        _ if let Ok(Some(num))  = num_seek(src) => num,
+        _ if let Ok(Some(text)) = text_seek(src) => text,
+        _ => {
+            for_each!((_, c) in char_indices(src) => if !is_whitespace(c) {
+                return Err(Unexpected(c))
+            });
+            return Ok(None)
+        }
+    }))
+}
+pub const fn is_whitespace (c: char) -> bool {
+    matches!(c, ' '|'\n'|'\r'|'\t')
+}
+pub const fn no_trailing_non_whitespace (source: &str, offset: usize) -> DslResult<()> {
+    let tail = str_range(source, offset, source.len());
+    for_each!((_, c) in char_indices(tail) => if !is_whitespace(c) {
+        return Err(Unexpected(c))
+    });
+    Ok(())
+}
diff --git a/dsl/src/dsl_parse.rs b/dsl/src/dsl_parse.rs
deleted file mode 100644
index 25eef20..0000000
--- a/dsl/src/dsl_parse.rs
+++ /dev/null
@@ -1,183 +0,0 @@
-use crate::*;
-
-macro_rules! iter_chars(($source:expr => |$i:ident, $c:ident|$val:expr)=>{
-    while let Some((($i, $c), next)) = char_indices($source).next() {
-        $source = next.as_str(); $val } });
-
-macro_rules! def_peek_seek(($peek:ident, $seek:ident, $seek_start:ident, $seek_length:ident)=>{
-    /// Find a slice corrensponding to a syntax token.
-    pub const fn $peek (source: &str) -> DslPerhaps<&str> {
-        match $seek(source) {
-            Ok(Some((start, length))) => Ok(Some(str_range(source, start, start + length))),
-            Ok(None) => Ok(None),
-            Err(e) => Err(e) } }
-    /// Find a start and length corresponding to a syntax token.
-    pub const fn $seek (source: &str) -> DslPerhaps<(usize, usize)> {
-        match $seek_start(source) {
-            Ok(Some(start)) => match $seek_length(str_range(source, start, source.len() - start)) {
-                Ok(Some(length)) => Ok(Some((start, length))),
-                Ok(None) => Ok(None),
-                Err(e) => Err(e),
-            },
-            Ok(None) => Ok(None),
-            Err(e) => Err(e) } } });
-
-def_peek_seek!(exp_peek, exp_seek, exp_seek_start, exp_seek_length);
-pub const fn is_exp_start (c: char) -> bool { matches!(c, '(') }
-pub const fn is_exp_end (c: char) -> bool { matches!(c, ')') }
-pub const fn exp_seek_start (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_exp_start(c) {
-        return Ok(Some(i))
-    } else if !is_whitespace(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn exp_seek_length (mut source: &str) -> DslPerhaps<usize> {
-    let mut depth = 0;
-    iter_chars!(source => |i, c| if is_exp_start(c) {
-        depth += 1;
-    } else if is_exp_end(c) {
-        if depth == 0 {
-            return Err(Unexpected(c))
-        } else if depth == 1 {
-            return Ok(Some(i))
-        } else {
-            depth -= 1;
-        }
-    });
-    Ok(None)
-}
-
-def_peek_seek!(sym_peek,  sym_seek,  sym_seek_start,  sym_seek_length);
-pub const fn is_sym_start (c: char) -> bool { matches!(c, ':'|'@') }
-pub const fn is_sym_char (c: char) -> bool { matches!(c, 'a'..='z'|'A'..='Z'|'0'..='9'|'-') }
-pub const fn is_sym_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
-pub const fn sym_seek_start (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_sym_start(c) {
-        return Ok(Some(i))
-    } else if !is_whitespace(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn sym_seek_length (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_sym_end(c) {
-        return Ok(Some(i))
-    } else if !is_sym_char(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-
-def_peek_seek!(key_peek,  key_seek,  key_seek_start,  key_seek_length);
-pub const fn is_key_start (c: char) -> bool { matches!(c, '/'|'a'..='z') }
-pub const fn is_key_char (c: char) -> bool { matches!(c, 'a'..='z'|'0'..='9'|'-'|'/') }
-pub const fn is_key_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
-pub const fn key_seek_start (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_key_start(c) {
-        return Ok(Some(i))
-    } else if !is_whitespace(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn key_seek_length (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_key_end(c) {
-        return Ok(Some(i))
-    } else if !is_key_char(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-
-def_peek_seek!(text_peek, text_seek, text_seek_start, text_seek_length);
-pub const fn is_text_start (c: char) -> bool { matches!(c, '"') }
-pub const fn is_text_end (c: char) -> bool { matches!(c, '"') }
-pub const fn text_seek_start (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_text_start(c) {
-        return Ok(Some(i))
-    } else if !is_whitespace(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn text_seek_length (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_text_end(c) { return Ok(Some(i)) });
-    Ok(None)
-}
-
-def_peek_seek!(num_peek,  num_seek,  num_seek_start,  num_seek_length);
-pub const fn num_seek_start (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_digit(c) {
-        return Ok(Some(i));
-    } else if !is_whitespace(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn num_seek_length (mut source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_num_end(c) {
-        return Ok(Some(i))
-    } else if !is_digit(c) {
-        return Err(Unexpected(c))
-    });
-    Ok(None)
-}
-pub const fn is_digit (c: char) -> bool { matches!(c, '0'..='9') }
-pub const fn is_num_end (c: char) -> bool { matches!(c, ' '|'\n'|'\r'|'\t'|')') }
-pub const fn to_number <D: Dsl> (digits: &str) -> Result<usize, DslError> {
-    let mut iter = char_indices(digits);
-    let mut value = 0;
-    while let Some(((_, c), next)) = iter.next() {
-        match to_digit(c) {
-            Ok(digit) => value = 10 * value + digit,
-            Err(e) => return Err(e),
-        }
-        iter = next;
-    }
-    Ok(value)
-}
-pub const fn to_digit (c: char) -> Result<usize, DslError> {
-    Ok(match c {
-        '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
-        '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9,
-        _ => return Err(Unexpected(c))
-    })
-}
-
-pub const fn peek (mut src: &str) -> DslPerhaps<&str> {
-    Ok(Some(match () {
-        _ if let Ok(Some(exp))  = exp_peek(src) => exp,
-        _ if let Ok(Some(sym))  = sym_peek(src) => sym,
-        _ if let Ok(Some(key))  = key_peek(src) => key,
-        _ if let Ok(Some(num))  = num_peek(src) => num,
-        _ if let Ok(Some(text)) = text_peek(src) => text,
-        _ => {
-            iter_chars!(src => |_i, c| if !is_whitespace(c) {
-                return Err(Unexpected(c))
-            });
-            return Ok(None)
-        }
-    }))
-}
-
-pub const fn seek (mut src: &str) -> DslPerhaps<(usize, usize)> {
-    Ok(Some(match () {
-        _ if let Ok(Some(exp))  = exp_seek(src) => exp,
-        _ if let Ok(Some(sym))  = sym_seek(src) => sym,
-        _ if let Ok(Some(key))  = key_seek(src) => key,
-        _ if let Ok(Some(num))  = num_seek(src) => num,
-        _ if let Ok(Some(text)) = text_seek(src) => text,
-        _ => {
-            iter_chars!(src => |_i, c| if !is_whitespace(c) {
-                return Err(Unexpected(c))
-            });
-            return Ok(None)
-        }
-    }))
-}
-
-pub const fn is_whitespace (c: char) -> bool {
-    matches!(c, ' '|'\n'|'\r'|'\t')
-}
diff --git a/dsl/src/dsl_test.rs b/dsl/src/dsl_test.rs
index e69de29..05f0308 100644
--- a/dsl/src/dsl_test.rs
+++ b/dsl/src/dsl_test.rs
@@ -0,0 +1,97 @@
+use crate::*;
+macro_rules!is_some(($exp:expr, $val:expr)=>{assert_eq!($exp, Ok(Some($val)))};);
+macro_rules!is_none(($exp:expr)=>{assert_eq!($exp, Ok(None))};);
+macro_rules!is_err(($exp:expr)=>{assert!($exp.is_err())};
+                   ($exp:expr, $err:expr)=>{assert_eq!($exp, Err($err))};);
+#[test] fn test_exp () -> Result<(), DslError> {
+    let e0 = DslError::Unexpected('a');
+    let e1 = DslError::Unexpected('(');
+    let e2 = DslError::Unexpected('b');
+    let e3 = DslError::Unexpected('d');
+    let check = |src: &str, key, exp, head, tail|{
+        assert_eq!(src.key(),  key,  "{src}");
+        assert_eq!(src.exp(),  exp,  "{src}");
+        assert_eq!(src.head(), head, "{src}");
+        assert_eq!(src.tail(), tail, "{src}");
+    };
+    check("a",             Ok(Some("a")), Err(e0), Ok(Some("a")), Ok(None));
+    check("(a)",           Err(e1), Ok(Some("a")), Ok(Some("(a)")), Ok(None));
+    check("a b c",         Err(e2), Err(e0), Ok(Some("a")), Ok(Some("b c")));
+    check("(a b c)",       Err(e1), Ok(Some("a b c")), Ok(Some("(a b c)")), Ok(None));
+    check("(a b c) d e f", Err(e1), Err(e3), Ok(Some("(a b c)")), Ok(Some("d e f")));
+    check("a (b c d) e f", Err(e1), Err(e0), Ok(Some("a")), Ok(Some("(b c d) e f")));
+
+    assert!(is_whitespace(' '));
+    assert!(!is_key_start(' '));
+    assert!(is_key_start('f'));
+
+    is_some!(key_seek_start("foo"),   0);
+    is_some!(key_seek_start("foo "),  0);
+    is_some!(key_seek_start(" foo "), 1);
+    is_some!(key_seek_length(&" foo "[1..]), 3);
+    is_some!(key_seek("foo"),   (0, 3));
+    is_some!(key_peek("foo"),   "foo");
+    is_some!(key_seek("foo "),  (0, 3));
+    is_some!(key_peek("foo "),  "foo");
+    is_some!(key_seek(" foo "), (1, 3));
+    is_some!(key_peek(" foo "), "foo");
+
+    is_err!("(foo)".key());
+    is_err!("foo".exp());
+
+    is_some!("(foo)".exp(), "foo");
+    is_some!("(foo)".head(), "(foo)");
+    is_none!("(foo)".tail());
+
+    is_some!("(foo bar baz)".exp(),  "foo bar baz");
+    is_some!("(foo bar baz)".head(), "(foo bar baz)");
+    is_none!("(foo bar baz)".tail());
+
+    is_some!("(foo bar baz)".exp().head(), "foo");
+    is_some!("(foo bar baz)".exp().tail(), "bar baz");
+    is_some!("(foo bar baz)".exp().tail().head(), "bar");
+    is_some!("(foo bar baz)".exp().tail().tail(), "baz");
+
+    is_err!("foo".exp());
+    is_some!("foo".key(), "foo");
+    is_some!(" foo".key(), "foo");
+    is_some!(" foo ".key(), "foo");
+
+    is_some!(" foo ".head(), "foo");
+    //assert_eq!(" foo ".head().head(), Ok(None));
+    is_none!(" foo ".head().tail());
+    is_none!(" foo ".tail());
+    is_none!(" foo ".tail().head());
+    is_none!(" foo ".tail().tail());
+
+    assert_eq!(" foo bar ".head(),        Ok(Some("foo")));
+    //assert_eq!(" foo bar ".head().head(), Ok(None));
+    assert_eq!(" foo bar ".head().tail(), Ok(None));
+    assert_eq!(" foo bar ".tail(),        Ok(Some(" bar ")));
+    assert_eq!(" foo bar ".tail().head(), Ok(Some("bar")));
+    assert_eq!(" foo bar ".tail().tail(), Ok(None));
+
+    assert_eq!(" (foo) ".head(),               Ok(Some("(foo)")));
+    //assert_eq!(" (foo) ".head().head(),        Ok(Some("foo")));
+    //assert_eq!(" (foo) ".head().head().head(), Ok(None));
+    assert_eq!(" (foo) ".tail(),               Ok(None));
+
+    assert_eq!(" (foo) (bar) ".head(),               Ok(Some("(foo)")));
+    //assert_eq!(" (foo) (bar) ".head().head(),        Ok(Some("foo")));
+    //assert_eq!(" (foo) (bar) ".head().head().head(), Ok(None));
+    is_some!(" (foo) (bar) ".tail(),                     " (bar) ");
+    is_some!(" (foo) (bar) ".tail().head(),              "(bar)");
+    is_some!(" (foo) (bar) ".tail().head().head(),       "(bar)");
+    is_some!(" (foo) (bar) ".tail().head().exp(),        "bar");
+    is_some!(" (foo) (bar) ".tail().head().exp().head(), "bar");
+
+    is_some!(" (foo bar baz) ".head(),              "(foo bar baz)");
+    is_some!(" (foo bar baz) ".head().head(),       "(foo bar baz)");
+    is_some!(" (foo bar baz) ".exp(),               "foo bar baz");
+    is_some!(" (foo bar baz) ".exp().head(),        "foo");
+    is_some!(" (foo bar baz) ".exp().tail(),        "bar baz");
+    is_some!(" (foo bar baz) ".exp().tail().head(), "bar");
+    is_some!(" (foo bar baz) ".exp().tail().tail(), "baz");
+    is_none!(" (foo bar baz) ".tail());
+    Ok(())
+}
diff --git a/input/src/lib.rs b/input/src/lib.rs
index f219c64..800ee2f 100644
--- a/input/src/lib.rs
+++ b/input/src/lib.rs
@@ -1,13 +1,6 @@
 #![feature(associated_type_defaults)]
 #![feature(if_let_guard)]
-
-pub(crate) use std::fmt::Debug;
-pub(crate) use std::sync::Arc;
-pub(crate) use std::collections::BTreeMap;
-pub(crate) use std::path::{Path, PathBuf};
-pub(crate) use std::fs::exists;
 pub(crate) use tengri_core::*;
-
 mod input_macros;
 mod input; pub use self::input::*;
 #[cfg(feature = "dsl")] pub(crate) use ::tengri_dsl::*;
diff --git a/tui/src/lib.rs b/tui/src/lib.rs
index e3792f1..50d7eeb 100644
--- a/tui/src/lib.rs
+++ b/tui/src/lib.rs
@@ -1,28 +1,17 @@
 #![feature(type_changing_struct_update)]
-
 mod tui_engine;  pub use self::tui_engine::*;
 mod tui_content; pub use self::tui_content::*;
-
 pub(crate) use ::tengri_core::*;
-
-pub use ::tengri_input as input;
-pub(crate) use ::tengri_input::*;
-
-pub use ::tengri_output as output;
-pub(crate) use ::tengri_output::*;
-
+pub use ::tengri_input as input; pub(crate) use ::tengri_input::*;
+pub use ::tengri_output as output; pub(crate) use ::tengri_output::*;
 pub(crate) use atomic_float::AtomicF64;
-
 pub use ::better_panic; pub(crate) use ::better_panic::{Settings, Verbosity};
-
 pub use ::palette; pub(crate) use ::palette::{*, convert::*, okhsl::*};
-
 pub use ::crossterm; pub(crate) use ::crossterm::{
     ExecutableCommand,
     terminal::{EnterAlternateScreen, LeaveAlternateScreen, enable_raw_mode, disable_raw_mode},
     event::{Event, KeyEvent, KeyCode, KeyModifiers, KeyEventKind, KeyEventState},
 };
-
 pub use ::ratatui; pub(crate) use ratatui::{
     prelude::{Color, Style, Buffer},
     style::Modifier,
@@ -30,10 +19,8 @@ pub use ::ratatui; pub(crate) use ratatui::{
     layout::{Size, Rect},
     buffer::Cell
 };
-
 pub(crate) use std::sync::{Arc, RwLock, atomic::{AtomicBool, Ordering::*}};
 pub(crate) use std::io::{stdout, Stdout};
-
 #[cfg(test)] #[test] fn test_tui_engine () -> Usually<()> {
     use crate::*;
     //use std::sync::{Arc, RwLock};
@@ -55,7 +42,6 @@ pub(crate) use std::io::{stdout, Stdout};
     //engine.run(&state)?;
     Ok(())
 }
-
 #[cfg(test)] #[test] fn test_parse_key () {
     //use KeyModifiers as Mods;
     let _test = |x: &str, y|assert_eq!(KeyMatcher::new(x).build(), Some(Event::Key(y)));