diff --git a/Cargo.toml b/Cargo.toml
index a204087..e491b53 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,6 +22,7 @@ version = "0.13.0"
 edition = "2024"
 
 [workspace.dependencies]
+anyhow          = { version = "1.0" }
 atomic_float    = { version = "1" }
 better-panic    = { version = "0.3.0" }
 const_panic     = { version = "0.2.12", features = [ "derive" ] }
diff --git a/dsl/src/dsl.rs b/dsl/src/dsl.rs
index 6348d49..71e9a9f 100644
--- a/dsl/src/dsl.rs
+++ b/dsl/src/dsl.rs
@@ -16,331 +16,27 @@ pub(crate) use ::{
 };
 pub(crate) use self::DslError::*;
 mod dsl_conv; pub use self::dsl_conv::*;
-mod dsl_type;
+mod dsl_ns;   pub use self::dsl_ns::*;
+mod dsl_src;  pub use self::dsl_src::*;
+mod dsl_type; pub use self::dsl_type::*;
 #[cfg(test)] mod dsl_test;
 /// DSL-specific result type.
 pub type DslResult<T> = Result<T, DslError>;
 /// DSL-specific optional result type.
 pub type DslPerhaps<T> = Result<Option<T>, DslError>;
-/// Namespace mapping.
-pub struct DslNsMap<'t, T: 't>(pub &'t [(&'t str, T)]);
-impl<'t, T: 't> DslNsMap<'t, T> {
-    /// Populate a namespace.
-    pub const fn new (data: &'t [(&'t str, T)]) -> Self {
-        Self(data) // TODO build search index
-    }
-}
-pub trait DslNs<'t, T: 't>: 't {
-    /// Known symbols.
-    const SYMS: DslNsMap<'t, fn (&'t Self)->Perhaps<T>> = DslNsMap::new(&[]);
-    /// Known expressions.
-    const EXPS: DslNsMap<'t, fn (&'t Self, &str)->Perhaps<T>> = DslNsMap::new(&[]);
-    /// Resolve a symbol if known.
-    fn from_sym <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
-        if let Some(dsl) = dsl.sym()? {
-            for (sym, get) in Self::SYMS.0 { if dsl == *sym { return get(self) } }
-        }
-        return Ok(None)
-    }
-    /// Resolve an expression if known.
-    fn from_exp <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
-        if let Some(exp) = dsl.exp()? {
-            for (key, value) in Self::EXPS.0.iter() {
-                if exp.head() == Ok(Some(key)) { return value(self, exp.tail()?.unwrap_or("")) }
-            }
-        }
-        return Ok(None)
-    }
-    /// Resolve an expression or symbol.
-    fn from <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
-        if let Ok(Some(src)) = dsl.src() {
-            if let Ok(Some(src)) = src.sym() {
-                self.from_sym(src)
-            } else {
-                self.from_exp(src)
-            }
-        } else {
-            Ok(None)
-        }
-    }
-}
-/// Define a namespace:
-#[macro_export] macro_rules! dsl_ns (
-    (|$state:ident : $State: ty| $($Type:ty $(=> { $($pat:tt => $body:expr),* $(,)? })?;)+) => {
-        $(dsl_ns!(|$state: $State| -> $Type { $( $($pat => $body),* )? });)+
-    };
-    (|$state:ident : $State: ty| -> $Type:ty { $($pat:tt => $body:expr),* $(,)? }) => {
-        impl<'t> DslNs<'t, $Type> for $State {
-            const SYMS: DslNsMap<'t, fn (&'t $State)->Perhaps<$Type>> =
-                DslNsMap::new(&[$(dsl_ns!{@sym ($state: $State) -> $Type { $pat => $body }}),*]);
-            const EXPS: DslNsMap<'t, fn (&'t $State, &str)->Perhaps<$Type>> =
-                DslNsMap::new(&[$(dsl_ns!{@exp ($state: $State) -> $Type { $pat => $body }}),*]);
-        }
-    };
-    (@sym ($state:ident: $State:ty) -> $Type:ty { $sym:literal => $body:expr }) => {
-        ($sym, |$state|Ok(Some($body)))
-    };
-    (@exp ($state:ident: $State:ty) -> $Type:ty {
-        ($head:literal $(,$arg:ident:$ty:ty)* $(,)*) => $body:expr
-    }) => { ($head, |$state, tail: &str|{
-        $(
-            let head = tail.head()?.unwrap_or_default();
-            let $arg: $ty = if let Some(arg) = $state.from(&head)? {
-                arg
-            } else {
-                return Err(format!("missing argument: {}", stringify!($arg)).into())
-            };
-            let tail = tail.tail()?.unwrap_or_default();
-        )*
-        Ok(Some($body))
-    }) };
-    (@sym ($state:ident: $State:ty) -> $Type:ty { $pat:tt => $body:expr }) => {
-        ("", |_|Ok(None))
-    };
-    (@exp ($state:ident: $State:ty) -> $Type:ty { $pat:tt => $body:expr }) => {
-        ("", |_, _|Ok(None))
-    };
-);
-// Some things that can be DSL source:
-impl     Dsl for String   { fn src (&self) -> DslPerhaps<&str> { Ok(Some(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())) } }
-
-// Designates a string as parsable DSL.
-flex_trait!(Dsl: Debug + Send + Sync + Sized { fn src (&self) -> DslPerhaps<&str> { unreachable!("Dsl::src default impl") } });
-impl<D: Dsl> Dsl for Option<D> {
-    fn src (&self) -> DslPerhaps<&str> {Ok(if let Some(dsl) = self { dsl.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)}}
-}
-
 /// DSL-specific error codes.
 #[derive(Error, Debug, Copy, Clone, PartialEq, PanicFmt)]
 pub enum DslError {
-    #[error("parse failed: not implemented")] Unimplemented,
-    #[error("parse failed: empty")] Empty,
-    #[error("parse failed: incomplete")] Incomplete,
-    #[error("parse failed: unexpected character '{0}'")] Unexpected(char, Option<usize>, Option<&'static str>),
-    #[error("parse failed: error #{0}")] Code(u8),
-    #[error("end reached")] End
-}
-
-fn ok_flat <T> (x: Option<DslPerhaps<T>>) -> DslPerhaps<T> { Ok(x.transpose()?.flatten()) }
-pub const fn is_space (c: char) -> bool {
-    matches!(c, ' '|'\n'|'\r'|'\t')
-}
-pub const fn no_trailing_non_space (src: &str, offset: usize, context: Option<&'static str>) -> DslResult<()> {
-    Ok(for_each!((i, c) in char_indices(str_range(src, offset, src.len())) => if !is_space(c) {
-        return Err(Unexpected(c, Some(offset + i), if let Some(context) = context {
-            Some(context)
-        } else {
-            Some("trailing non-space")
-        }))
-    }))
-}
-
-pub const fn peek (src: &str) -> DslPerhaps<&str> {
-    Ok(Some(if let Ok(Some(exp))  = exp_peek(src)  { exp  } else
-            if let Ok(Some(sym))  = sym_peek(src)  { sym  } else
-            if let Ok(Some(key))  = key_peek(src)  { key  } else
-            if let Ok(Some(num))  = num_peek(src)  { num  } else
-            if let Ok(Some(text)) = text_peek(src) { text } else
-            if let Err(e) = no_trailing_non_space(src, 0, Some("peek")) { return Err(e) }
-            else { return Ok(None) }))
-}
-pub const fn seek (src: &str) -> DslPerhaps<(usize, usize)> {
-    Ok(Some(if let Ok(Some(exp))  = exp_seek(src)  { exp  } else
-            if let Ok(Some(sym))  = sym_seek(src)  { sym  } else
-            if let Ok(Some(key))  = key_seek(src)  { key  } else
-            if let Ok(Some(num))  = num_seek(src)  { num  } else
-            if let Ok(Some(text)) = text_seek(src) { text } else
-            if let Err(e) = no_trailing_non_space(src, 0, Some("seek")) { return Err(e) }
-            else { return Ok(None) }))
-}
-pub const fn peek_tail (src: &str) -> DslPerhaps<&str> {
-    match seek(src) {
-        Err(e) => Err(e),
-        Ok(None) => Ok(None),
-        Ok(Some((start, length))) => {
-            let tail = str_range(src, start + length, src.len());
-            for_each!((_i, c) in char_indices(tail) => if !is_space(c) { return Ok(Some(tail)) });
-            Ok(None)
-        },
-    }
-}
-
-pub const fn is_exp_start (c: char) -> bool { c == '(' }
-pub const fn is_exp_end (c: char) -> bool { c == ')' }
-dsl_type!(DslExp {
-    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))}
-    /// my other car is a cdr :<
-    fn each (&self, mut cb: impl FnMut(&str)->Usually<()>) -> Usually<()> {
-        Ok(if let Some(head) = self.head()? {
-            cb(head)?;
-            if let Some(tail) = self.tail()? {
-                tail.each(cb)?;
-            }
-        })
-    }
-} {
-    pub const fn exp_peek      [generated];
-    pub const fn exp_peek_only [generated];
-    pub const fn exp_seek      [generated];
-    pub const fn exp_seek_start (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_exp_start(c) { return Ok(Some(i)) } else
-            if !is_space(c) { return Err(Unexpected(c, Some(i), Some("expected expression start"))) });
-        Ok(None)
-    }
-    pub const fn exp_seek_length (src) {
-        let mut depth = 0;
-        for_each!((i, c) in char_indices(src) =>
-            if is_exp_start(c) { depth += 1; } else
-            if is_exp_end(c) {
-                if depth == 0 {
-                    return Err(Unexpected(c, Some(i), Some("expected expression end")))
-                } else if depth == 1 {
-                    return Ok(Some(i + 1))
-                } else {
-                    depth -= 1;
-                }
-            });
-        Err(Incomplete)
-    }
-});
-
-pub const fn exp_peek_inner (src: &str) -> DslPerhaps<&str> {
-    match exp_peek(src) {
-        Ok(Some(peeked)) => {
-            let len = peeked.len();
-            let start = if len > 0 { 1 } else { 0 };
-            Ok(Some(str_range(src, start, start + len.saturating_sub(2))))
-        },
-        e => e
-    }
-}
-
-pub const fn exp_peek_inner_only (src: &str) -> DslPerhaps<&str> {
-    match exp_seek(src) {
-        Err(e) => Err(e),
-        Ok(None) => Ok(None),
-        Ok(Some((start, length))) => {
-            if let Err(e) = no_trailing_non_space(src, start + length, Some("exp_peek_inner_only")) { return Err(e) }
-            let peeked = str_range(src, 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_sym_start (c: char) -> bool { matches!(c, ':'|'@') }
-pub const fn is_sym_char (c: char) -> bool { is_sym_start(c) || matches!(c, 'a'..='z'|'A'..='Z'|'0'..='9'|'-'|'/') }
-pub const fn is_sym_end (c: char) -> bool { is_space(c) || matches!(c, ')') }
-dsl_type!(DslSym {
-    fn sym (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(sym_peek_only))}
-} {
-    pub const fn sym_peek      [generated];
-    pub const fn sym_peek_only [generated];
-    pub const fn sym_seek      [generated];
-    pub const fn sym_seek_start (src) {
-        for_each!((i, c) in char_indices(src) => if
-            is_sym_start(c) { return Ok(Some(i)) } else
-            if !is_space(c) { return Err(Unexpected(c, Some(i), Some("sym_seek_start"))) });
-        Ok(None)
-    }
-    pub const fn sym_seek_length (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_sym_end(c) { return Ok(Some(i)) } else
-            if !is_sym_char(c) { return Err(Unexpected(c, Some(i), Some("sym_seek_length"))) });
-        Ok(Some(src.len()))
-    }
-});
-
-pub const fn is_text_start (c: char) -> bool { matches!(c, '"') }
-pub const fn is_text_end (c: char) -> bool { matches!(c, '"') }
-dsl_type!(DslText {
-    fn text (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(text_peek_only)) }
-} {
-    pub const fn text_peek      [generated];
-    pub const fn text_peek_only [generated];
-    pub const fn text_seek      [generated];
-    pub const fn text_seek_start (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_text_start(c) { return Ok(Some(i)) } else
-            if !is_space(c)     { return Err(Unexpected(c, Some(i), None)) });
-        Ok(None)
-    }
-    pub const fn text_seek_length (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_text_end(c) { return Ok(Some(i)) });
-        Ok(None)
-    }
-});
-
-pub const fn is_key_start (c: char) -> bool { matches!(c, '/'|('a'..='z')) }
-pub const fn is_key_char (c: char) -> bool { is_key_start(c) || matches!(c, '0'..='9'|'-') }
-pub const fn is_key_end (c: char) -> bool { !is_key_char(c) }
-dsl_type!(DslKey {
-    fn key (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(key_peek_only)) }
-} {
-    pub const fn key_peek      [generated];
-    pub const fn key_peek_only [generated];
-    pub const fn key_seek      [generated];
-    pub const fn key_seek_start (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_key_start(c) { return Ok(Some(i)) } else
-            if !is_space(c)    { return Err(Unexpected(c, Some(i), None)) });
-        Ok(None)
-    }
-    pub const fn key_seek_length (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_key_end(c)   { return Ok(Some(i)) } else
-            if !is_key_char(c) { return Err(Unexpected(c, Some(i), None)) });
-        Ok(Some(src.len()))
-    }
-});
-
-dsl_type!(DslNum {
-    fn num (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(num_peek_only))}
-} {
-    pub const fn num_peek      [generated];
-    pub const fn num_peek_only [generated];
-    pub const fn num_seek      [generated];
-    pub const fn num_seek_start (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_digit(c)  { return Ok(Some(i)); } else
-            if !is_space(c) { return Err(Unexpected(c, Some(i), None)) });
-        Ok(None)
-    }
-    pub const fn num_seek_length (src) {
-        for_each!((i, c) in char_indices(src) =>
-            if is_num_end(c) { return Ok(Some(i)) } else
-            if !is_digit(c)  { return Err(Unexpected(c, Some(i), None)) });
-        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, None, Some("parse digit")))
-    })
+    #[error("parse failed: not implemented")]
+    Unimplemented,
+    #[error("parse failed: empty")]
+    Empty,
+    #[error("parse failed: incomplete")]
+    Incomplete,
+    #[error("parse failed: unexpected character '{0}'")]
+    Unexpected(char, Option<usize>, Option<&'static str>),
+    #[error("parse failed: error #{0}")]
+    Code(u8),
+    #[error("end reached")]
+    End
 }
diff --git a/dsl/src/dsl_ns.rs b/dsl/src/dsl_ns.rs
new file mode 100644
index 0000000..f179905
--- /dev/null
+++ b/dsl/src/dsl_ns.rs
@@ -0,0 +1,118 @@
+use crate::*;
+/// Define a namespace:
+#[macro_export] macro_rules! dsl_ns (
+    // Special form for numeric types
+    (num |$state:ident : $State: ty| $($($num:lifetime)? $Type:ty $(=> { $(
+        $pat:tt => $body:expr
+    ),* $(,)? })?;)+) => {
+        $(dsl_ns!(num |$state: $State| -> $($num)? $Type { $( $($pat => $body),* )? });)+
+    };
+    // Special form for numeric types
+    (num |$state:ident : $State: ty| -> $Type:ty { $( $pat:tt => $body:expr ),* $(,)? }) => {
+        impl<'t> DslNs<'t, $Type> for $State {
+            const SYMS: DslNsMap<'t, fn (&'t $State)->Perhaps<$Type>> =
+                DslNsMap::new(&[$(dsl_ns!{@sym ($state: $State) -> $Type { $pat => $body }}),*]);
+            const EXPS: DslNsMap<'t, fn (&'t $State, &str)->Perhaps<$Type>> =
+                DslNsMap::new(&[$(dsl_ns!{@exp ($state: $State) -> $Type { $pat => $body }}),*]);
+            fn from <D: Dsl> (&'t self, dsl: D) -> Perhaps<$Type> {
+                if let Ok(Some(src)) = dsl.src() {
+                    if let Ok(Some(num)) = src.num() {
+                        Ok(Some(to_number(num)? as $Type))
+                    } else if let Ok(Some(src)) = src.sym() {
+                        self.from_sym(src)
+                    } else {
+                        self.from_exp(src)
+                    }
+                } else {
+                    Ok(None)
+                }
+            }
+        }
+    };
+    // A namespace may resolve one or more types.
+    (|$state:ident : $State: ty| $($Type:ty $(=> { $( $pat:tt => $body:expr ),* $(,)? })? ;)+) => {
+        $(dsl_ns!(|$state: $State| -> $Type { $( $($pat => $body),* )? });)+
+    };
+    // Regular form for single type
+    (|$state:ident : $State: ty| -> $Type:ty { $( $pat:tt => $body:expr ),* $(,)? }) => {
+        impl<'t> DslNs<'t, $Type> for $State {
+            const SYMS: DslNsMap<'t, fn (&'t $State)->Perhaps<$Type>> =
+                DslNsMap::new(&[$(dsl_ns!{@sym ($state: $State) -> $Type { $pat => $body }}),*]);
+            const EXPS: DslNsMap<'t, fn (&'t $State, &str)->Perhaps<$Type>> =
+                DslNsMap::new(&[$(dsl_ns!{@exp ($state: $State) -> $Type { $pat => $body }}),*]);
+        }
+    };
+    // Symbols only.
+    (@sym ($state:ident: $State:ty) -> $Type:ty {
+        $sym:literal => $body:expr
+    }) => {
+        ($sym, |$state|Ok(Some($body)))
+    };
+    // Expression handlers only.
+    (@exp ($state:ident: $State:ty) -> $Type:ty {
+        ($head:literal $(,$arg:ident:$ty:ty)* $(,)*) => $body:expr
+    }) => { ($head, |$state, tail: &str|{
+        $(
+            let head = tail.head()?.unwrap_or_default();
+            let $arg: $ty = if let Some(arg) = $state.from(&head)? {
+                arg
+            } else {
+                return Err(format!("missing argument: {}", stringify!($arg)).into())
+            };
+            let tail = tail.tail()?.unwrap_or_default();
+        )*
+        Ok(Some($body))
+    }) };
+    // Nothing else in symbols.
+    (@sym ($state:ident: $State:ty) -> $Type:ty { $pat:tt => $body:expr }) => {
+        ("", |_|Ok(None)) // FIXME don't emit at all
+    };
+    // Nothing else in expression handlers.
+    (@exp ($state:ident: $State:ty) -> $Type:ty { $pat:tt => $body:expr }) => {
+        ("", |_, _|Ok(None)) // FIXME don't emit at all
+    };
+
+);
+
+pub trait DslNs<'t, T: 't>: 't {
+    /// Known symbols.
+    const SYMS: DslNsMap<'t, fn (&'t Self)->Perhaps<T>> = DslNsMap::new(&[]);
+    /// Known expressions.
+    const EXPS: DslNsMap<'t, fn (&'t Self, &str)->Perhaps<T>> = DslNsMap::new(&[]);
+    /// Resolve a symbol if known.
+    fn from_sym <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
+        if let Some(dsl) = dsl.sym()? {
+            for (sym, get) in Self::SYMS.0 { if dsl == *sym { return get(self) } }
+        }
+        return Ok(None)
+    }
+    /// Resolve an expression if known.
+    fn from_exp <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
+        if let Some(exp) = dsl.exp()? {
+            for (key, value) in Self::EXPS.0.iter() {
+                if exp.head() == Ok(Some(key)) { return value(self, exp.tail()?.unwrap_or("")) }
+            }
+        }
+        return Ok(None)
+    }
+    /// Resolve an expression or symbol.
+    fn from <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
+        if let Ok(Some(src)) = dsl.src() {
+            if let Ok(Some(src)) = src.sym() {
+                self.from_sym(src)
+            } else {
+                self.from_exp(src)
+            }
+        } else {
+            Ok(None)
+        }
+    }
+}
+/// Namespace mapping.
+pub struct DslNsMap<'t, T: 't>(pub &'t [(&'t str, T)]);
+impl<'t, T: 't> DslNsMap<'t, T> {
+    /// Populate a namespace.
+    pub const fn new (data: &'t [(&'t str, T)]) -> Self {
+        Self(data) // TODO build search index
+    }
+}
diff --git a/dsl/src/dsl_src.rs b/dsl/src/dsl_src.rs
new file mode 100644
index 0000000..89b5fc9
--- /dev/null
+++ b/dsl/src/dsl_src.rs
@@ -0,0 +1,21 @@
+use crate::*;
+// Designates a string as parsable DSL.
+flex_trait!(Dsl: Debug + Send + Sync + Sized {
+    fn src (&self) -> DslPerhaps<&str> { unreachable!("Dsl::src default impl") }
+});
+// Some things that can be DSL source:
+impl Dsl for String {
+    fn src (&self) -> DslPerhaps<&str> { Ok(Some(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) -> DslPerhaps<&str> {Ok(if let Some(dsl) = self { dsl.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)}}
+}
diff --git a/dsl/src/dsl_type.rs b/dsl/src/dsl_type.rs
index 985c37b..94ff0ec 100644
--- a/dsl/src/dsl_type.rs
+++ b/dsl/src/dsl_type.rs
@@ -1,5 +1,50 @@
 use crate::*;
 
+fn ok_flat <T> (x: Option<DslPerhaps<T>>) -> DslPerhaps<T> {
+    Ok(x.transpose()?.flatten())
+}
+pub const fn is_space (c: char) -> bool {
+    matches!(c, ' '|'\n'|'\r'|'\t')
+}
+pub const fn no_trailing_non_space (
+    src: &str, offset: usize, context: Option<&'static str>
+) -> DslResult<()> {
+    Ok(for_each!((i, c) in char_indices(str_range(src, offset, src.len())) => if !is_space(c) {
+        return Err(Unexpected(c, Some(offset + i), if let Some(context) = context {
+            Some(context)
+        } else {
+            Some("trailing non-space")
+        }))
+    }))
+}
+pub const fn peek (src: &str) -> DslPerhaps<&str> {
+    Ok(Some(if let Ok(Some(exp))  = exp_peek(src)  { exp  } else
+            if let Ok(Some(sym))  = sym_peek(src)  { sym  } else
+            if let Ok(Some(num))  = num_peek(src)  { num  } else
+            if let Ok(Some(text)) = text_peek(src) { text } else
+            if let Err(e) = no_trailing_non_space(src, 0, Some("peek")) { return Err(e) }
+            else { return Ok(None) }))
+}
+pub const fn seek (src: &str) -> DslPerhaps<(usize, usize)> {
+    Ok(Some(if let Ok(Some(exp))  = exp_seek(src)  { exp  } else
+            if let Ok(Some(sym))  = sym_seek(src)  { sym  } else
+            if let Ok(Some(num))  = num_seek(src)  { num  } else
+            if let Ok(Some(text)) = text_seek(src) { text } else
+            if let Err(e) = no_trailing_non_space(src, 0, Some("seek")) { return Err(e) }
+            else { return Ok(None) }))
+}
+pub const fn peek_tail (src: &str) -> DslPerhaps<&str> {
+    match seek(src) {
+        Err(e) => Err(e),
+        Ok(None) => Ok(None),
+        Ok(Some((start, length))) => {
+            let tail = str_range(src, start + length, src.len());
+            for_each!((_i, c) in char_indices(tail) => if !is_space(c) { return Ok(Some(tail)) });
+            Ok(None)
+        },
+    }
+}
+
 #[macro_export] macro_rules! dsl_type (($T:ident { $($trait:tt)* } {
     pub const fn $peek:ident      $($_1:tt)?;
     pub const fn $peek_only:ident $($_2:tt)?;
@@ -113,9 +158,9 @@ pub const fn exp_peek_inner_only (src: &str) -> DslPerhaps<&str> {
     }
 }
 
-pub const fn is_sym_start (c: char) -> bool { matches!(c, ':'|'@') }
-pub const fn is_sym_char (c: char) -> bool { is_sym_start(c) || matches!(c, 'a'..='z'|'A'..='Z'|'0'..='9'|'-'|'/') }
-pub const fn is_sym_end (c: char) -> bool { is_space(c) || matches!(c, ')') }
+pub const fn is_sym_start (c: char) -> bool { is_sym_char(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 { is_space(c) || is_exp_end(c) }
 dsl_type!(DslSym {
     fn sym (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(sym_peek_only))}
 } {
@@ -201,7 +246,7 @@ dsl_type!(DslNum {
 });
 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> {
+pub const fn to_number (digits: &str) -> Result<usize, DslError> {
     let mut iter = char_indices(digits);
     let mut value = 0;
     while let Some(((_, c), next)) = iter.next() {
diff --git a/input/src/input_dsl.rs b/input/src/input_dsl.rs
index 24f6f1a..dd717c9 100644
--- a/input/src/input_dsl.rs
+++ b/input/src/input_dsl.rs
@@ -1,9 +1,5 @@
 use crate::*;
 use std::{sync::Arc, collections::BTreeMap, path::{Path, PathBuf}, fs::{exists, read_to_string}};
-/// Map of each event (e.g. key combination) to
-/// all command expressions bound to it by
-/// all loaded input layers.
-type EventMapImpl<E, C> = BTreeMap<E, Vec<Binding<C>>>;
 /// A collection of input bindings.
 ///
 /// Each contained layer defines a mapping from input event to command invocation
@@ -14,15 +10,33 @@ type EventMapImpl<E, C> = BTreeMap<E, Vec<Binding<C>>>;
 /// When the first non-conditional or true conditional binding is executed,
 /// that .event()binding's value is returned.
 #[derive(Debug)]
-pub struct EventMap<E, C>(pub EventMapImpl<E, C>);
+pub struct EventMap<E, C>(
+    /// Map of each event (e.g. key combination) to
+    /// all command expressions bound to it by
+    /// all loaded input layers.
+    pub BTreeMap<E, Vec<Binding<C>>>
+);
 /// An input binding.
 #[derive(Debug, Clone)]
 pub struct Binding<C> {
-    pub command:     C,
+    pub commands:    Arc<[C]>,
     pub condition:   Option<Condition>,
     pub description: Option<Arc<str>>,
     pub source:      Option<Arc<PathBuf>>,
 }
+impl<C> Binding<C> {
+    pub fn from_dsl (dsl: impl Dsl) -> Usually<Self> {
+        let command:     Option<C>            = None;
+        let condition:   Option<Condition>    = None;
+        let description: Option<Arc<str>>     = None;
+        let source:      Option<Arc<PathBuf>> = None;
+        if let Some(command) = command {
+            Ok(Self { commands: [command].into(), condition, description, source })
+        } else {
+            Err(format!("no command in {dsl:?}").into())
+        }
+    }
+}
 /// Input bindings are only returned if this evaluates to true
 #[derive(Clone)]
 pub struct Condition(Arc<Box<dyn Fn()->bool + Send + Sync>>);
@@ -59,72 +73,4 @@ impl<E: Clone + Ord, C> EventMap<E, C> {
             .map(|bb|bb.iter().filter(|b|b.condition.as_ref().map(|c|(c.0)()).unwrap_or(true)).next())
             .flatten()
     }
-    /// Create event map from path to text file.
-    pub fn load_from_path <'s> (
-        &'s mut self, path: impl AsRef<Path>
-    ) -> Usually<&'s mut Self> where Self: DslInto<C> + DslInto<E> {
-        if exists(path.as_ref())? {
-            let source = read_to_string(&path)?;
-            let path: Arc<PathBuf> = Arc::new(path.as_ref().into());
-            self.load_from_source(&source, &Some(&path))
-        } else {
-            return Err(format!("(e5) not found: {:?}", path.as_ref()).into())
-        }
-    }
-    /// Create event map from DSL tokenizer.
-    pub fn load_from_source (
-        &mut self, dsl: impl Dsl, path: &Option<&Arc<PathBuf>>
-    ) -> Usually<&mut Self> where Self: DslInto<C> + DslInto<E> {
-        dsl.each(|dsl|self.load_from_source_one(&dsl, path).map(move|_|()))?;
-        Ok(self)
-    }
-    /// Load one event binding into the event map.
-    pub fn load_from_source_one <'s> (
-        &'s mut self, dsl: impl Dsl, path: &Option<&Arc<PathBuf>>
-    ) -> Usually<&'s mut Self> where Self: DslInto<C> + DslInto<E> {
-        if let Some(exp)  = dsl.head()?.exp()?
-        && let Some(sym)  = exp.head()?.sym()?
-        && let Some(tail) = exp.tail()?
-        {
-            let event   = self.dsl_into_or_else(&sym, ||panic!())?;
-            let command = self.dsl_into_or_else(&tail, ||panic!())?;
-            Ok(self.add(event, Binding {
-                command, condition: None, description: None, source: path.cloned()
-            }))
-        } else {
-            Err(format!("unexpected: {:?}", dsl.head()?).into())
-        }
-    }
-        //})Ok(if let Some(sym) = dsl.head()?.exp()?.head()?.sym()? {
-            //if let Some(tail) = dsl.head()?.exp()?.tail()? {
-                //let event: E = sym.into();
-                //let binding: Binding<C> = Binding { command: tail.into(), condition: None, description: None, source: None };
-                //if let Some(bindings) = map.0.get_mut(&event) {
-                    //bindings.push(binding);
-                //} else {
-                    //map.0.insert(event, vec![binding]);
-                //}
-            //} else {
-                //panic!("empty binding: {}", dsl.head()?.exp()?.unwrap_or_default())
-            //}
-        //} else if let Some(ref text) = dsl.text()? {
-            //map.0.extend(Self::from_path(PathBuf::from(text))?.0);
-        //} else {
-            //return Err(format!("unexpected: {dsl:?}").into())
-        //}));
-        //Ok(map)
-    //}
-}
-impl<C> Binding<C> {
-    pub fn from_dsl (dsl: impl Dsl) -> Usually<Self> {
-        let command:     Option<C>            = None;
-        let condition:   Option<Condition>    = None;
-        let description: Option<Arc<str>>     = None;
-        let source:      Option<Arc<PathBuf>> = None;
-        if let Some(command) = command {
-            Ok(Self { command, condition, description, source })
-        } else {
-            Err(format!("no command in {dsl:?}").into())
-        }
-    }
 }