dsl: exp -> expr, sym -> word

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" ] }

dsl/README.md

@@ -95,7 +95,7 @@ or configuration statements, and look like this:
 
 ## implementation notes
 
-### `DslExp` trait behavior
+### `DslExpr` trait behavior
 
 this is the trait which differentiates "a thing" from
 "a thing that is many things".

dsl/src/dsl.rs

@@ -17,42 +17,37 @@ pub(crate) use ::{
 pub(crate) use self::DslError::*;
 mod dsl_conv; pub use self::dsl_conv::*;
 mod dsl_ns;   pub use self::dsl_ns::*;
-mod dsl_type;
+mod dsl_src;  pub use self::dsl_src::*;
 #[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>;
-// 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
+    #[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())
 }
-
-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<()> {
+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)
@@ -61,20 +56,17 @@ pub const fn no_trailing_non_space (src: &str, offset: usize, context: Option<&'
         }))
     }))
 }
-
 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
+    Ok(Some(if let Ok(Some(expr))  = expr_peek(src)  { expr  } else
+            if let Ok(Some(word))  = word_peek(src)  { word  } 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
+    Ok(Some(if let Ok(Some(expr))  = expr_seek(src)  { expr  } else
+            if let Ok(Some(word))  = word_seek(src)  { word  } 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) }
@@ -92,10 +84,56 @@ pub const fn peek_tail (src: &str) -> DslPerhaps<&str> {
     }
 }
 
-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))}
+#[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)?;
+    pub const fn $seek:ident      $($_3:tt)?;
+    pub const fn $seek_start:ident  ($source1:ident) $body1:block
+    pub const fn $seek_length:ident ($source2:ident) $body2:block
+})=>{
+    pub trait $T: Dsl { $($trait)* }
+    impl<D: Dsl> $T for D {}
+    /// 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_space(source, start + length, Some("peek_only")) { 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),
+            },
+        }
+    }
+    pub const fn $seek_start  ($source1: &str) -> DslPerhaps<usize> $body1
+    pub const fn $seek_length ($source2: &str) -> DslPerhaps<usize> $body2
+});
+
+pub const fn is_expr_start (c: char) -> bool { c == '(' }
+pub const fn is_expr_end (c: char) -> bool { c == ')' }
+dsl_type!(DslExpr {
+    fn expr  (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(expr_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 :<
@@ -108,20 +146,20 @@ dsl_type!(DslExp {
         })
     }
 } {
-    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) {
+    pub const fn expr_peek      [generated];
+    pub const fn expr_peek_only [generated];
+    pub const fn expr_seek      [generated];
+    pub const fn expr_seek_start (src) {
         for_each!((i, c) in char_indices(src) =>
-            if is_exp_start(c) { return Ok(Some(i)) } else
+            if is_expr_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) {
+    pub const fn expr_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 is_expr_start(c) { depth += 1; } else
+            if is_expr_end(c) {
                 if depth == 0 {
                     return Err(Unexpected(c, Some(i), Some("expected expression end")))
                 } else if depth == 1 {
@@ -134,8 +172,8 @@ dsl_type!(DslExp {
     }
 });
 
-pub const fn exp_peek_inner (src: &str) -> DslPerhaps<&str> {
-    match exp_peek(src) {
+pub const fn expr_peek_inner (src: &str) -> DslPerhaps<&str> {
+    match expr_peek(src) {
         Ok(Some(peeked)) => {
             let len = peeked.len();
             let start = if len > 0 { 1 } else { 0 };
@@ -145,12 +183,12 @@ pub const fn exp_peek_inner (src: &str) -> DslPerhaps<&str> {
     }
 }
 
-pub const fn exp_peek_inner_only (src: &str) -> DslPerhaps<&str> {
-    match exp_seek(src) {
+pub const fn expr_peek_inner_only (src: &str) -> DslPerhaps<&str> {
+    match expr_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) }
+            if let Err(e) = no_trailing_non_space(src, start + length, Some("expr_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 };
@@ -159,25 +197,26 @@ 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, ')') }
-dsl_type!(DslSym {
-    fn sym (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(sym_peek_only))}
+pub const fn is_word_char (c: char) -> bool {
+    matches!(c, 'a'..='z'|'A'..='Z'|'0'..='9'|'-'|'/'|'@'|':')
+}
+pub const fn is_word_end (c: char) -> bool {
+    is_space(c) || is_expr_end(c)
+}
+dsl_type!(DslWord {
+    fn word (&self) -> DslPerhaps<&str> {ok_flat(self.src()?.map(word_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) {
+    pub const fn word_peek      [generated];
+    pub const fn word_peek_only [generated];
+    pub const fn word_seek      [generated];
+    pub const fn word_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"))) });
+            is_word_char(c)  { return Ok(Some(i)) } else
+            if !is_space(c) { return Err(Unexpected(c, Some(i), Some("word_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"))) });
+    pub const fn word_seek_length (src) {
+        for_each!((i, c) in char_indices(src) => if !is_word_char(c) { return Ok(Some(i)) });
         Ok(Some(src.len()))
     }
 });
@@ -247,7 +286,7 @@ 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() {

dsl/src/dsl_ns.rs

@@ -1,74 +1,125 @@
 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(&[$(dsl_ns!{@word ($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 $Type))
+                    } else if let Ok(Some(src)) = src.word() {
+                        self.from_word(src)
+                    } else {
+                        self.from_exp(src)
+                    }
+                } else {
+                    Ok(None)
+                }
+            }
+        }
+    };
+    // A namespace may resolve one or more types.
+    (|$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(&[$(dsl_ns!{@word ($state: $State) -> $Type { $pat => $body }}),*]);
+            const EXPS: DslNsMap<'t, fn (&'t $State, &str)->Perhaps<$Type>> =
+                DslNsMap::new(&[$(dsl_ns!{@exp ($state: $State) -> $Type { $pat => $body }}),*]);
+        }
+    };
+    // Symbols only.
+    (@word ($state:ident: $State:ty) -> $Type:ty {
+        $word:literal => $body:expr
+    }) => {
+        ($word, |$state|Ok(Some($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) = $state.from(&head)? {
+                arg
+            } else {
+                return Err(format!("{}: missing argument: {}",
+                    stringify!($head),
+                    stringify!($arg)
+                ).into())
+            };
+            let tail = tail.tail()?.unwrap_or_default();
+        )*
+        Ok(Some($body))
+    }) };
+    // Nothing else in symbols.
+    (@word ($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
+    };
 
-/// Namespace where keys are symbols.
-pub trait DslSymNs<'t, T: 't>: 't {
-    /// Known symbold.
-    const SYMS: DslNs<'t, fn (&'t Self)->Perhaps<T>> = DslNs(&[]);
+);
+
+pub trait DslNs<'t, T: 't>: 't {
+    /// 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.word() {
+                self.from_word(src)
+            } else {
+                self.from_exp(src)
+            }
+        } else {
+            Ok(None)
+        }
+    }
     /// 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) } }
+    fn from_word <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
+        if let Some(dsl) = dsl.word()? {
+            for (word, get) in Self::SYMS.0 { if dsl == *word { return get(self) } }
         }
         return Ok(None)
     }
-}
-
-/// Define a symbol namespace.
-#[macro_export] macro_rules! dsl_sym_ns (
-    (|$state:ident:$State:ty| -> $Type:ty {$($lit:literal => $exp:expr),* $(,)?})=>{
-        impl<'t> DslSymNs<'t, $Type> for $State {
-            const SYMS: DslNs<'t, fn (&'t $State)->Perhaps<$Type>> = DslNs(&[
-                $(($lit, |$state: &$State|Ok(Some($exp)))),*
-            ]);
-        }
-    });
-
-/// Namespace where the keys are heads of expressions.
-pub trait DslExpNs<'t, T: 't>: 't {
-    /// Known expressions.
-    const EXPS: DslNs<'t, fn (&'t Self, &str)->Perhaps<T>> = DslNs(&[]);
     /// Resolve an expression if known.
     fn from_exp <D: Dsl> (&'t self, dsl: D) -> Perhaps<T> {
-        if let Some(exp) = dsl.exp()? {
-            //panic!("exp\n{:?}\n{:?}\n{:?}\n{:?}",
-                //exp.src(), exp.head(), exp.head().src(), Self::EXPS.0);
+        if let Some(head) = dsl.expr().head()? {
             for (key, value) in Self::EXPS.0.iter() {
-                println!("{key} {:?}", exp.head());
-                if exp.head() == Ok(Some(key)) { return value(self, exp.tail()?.unwrap_or("")) }
+                if head == *key {
+                    return value(self, dsl.expr().tail()?.unwrap_or(""))
                 }
             }
+        }
+        panic!("{dsl:?}");
         return Ok(None)
     }
+    /// Known symbols.
+    const SYMS: DslNsMap<'t, fn (&'t Self)->Perhaps<T>> = DslNsMap::new(&[]);
+    /// Known expressions.
+    const EXPS: DslNsMap<'t, fn (&'t Self, &str)->Perhaps<T>> = DslNsMap::new(&[]);
 }
-
-/// Define an expression namespace.
-#[macro_export] macro_rules! dsl_exp_ns (
-    (|$state:ident:$State:ty|->$Type:ty { $( (
-        $key:literal $(/ $sub:ident : $Sub:ty)? $(, $arg:ident:$ty:ty)* $(, ..$tail:ident)?
-    ) => $body:expr),* $(,)? }) => {
-        impl<'t> DslExpNs<'t, $Type> for $State {
-            const EXPS: DslNs<'t, fn (&'t $State, &str)->Perhaps<$Type>> = DslNs(&[ $(
-                ($key, |$state: &$State, mut tail: &str|{
-                    $(let $arg: $ty = if let Some(val) = dsl_next(&mut tail)? {
-                        val
-                    } else {
-                        return Err(format!("missing arg: {}", stringify!($arg)).into())
-                    };)*
-                    $(let $tail = tail;)?
-                    Ok(Some($body))
-                })
-            ),* ]);
+/// Namespace mapping.
+#[derive(Debug)]
+pub struct DslNsMap<'t, T: Debug + 't>(pub &'t [(&'t str, T)]);
+impl<'t, T: Debug + 't> DslNsMap<'t, T> {
+    /// Populate a namespace.
+    pub const fn new (data: &'t [(&'t str, T)]) -> Self {
+        Self(data) // TODO build search index
     }
-    });
-
-pub fn dsl_next <T> (dsl: &mut impl Dsl) -> DslPerhaps<T> {
-    todo!()
 }
-
-/// Namespace.
-///
-/// Currently linearly searched.
-/// Maybe it's better to use a trie.
-/// I don't think there's a `const` trie in Rust?
-/// Oughtta be.
-pub struct DslNs<'t, T: 't>(pub &'t [(&'t str, T)]);

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)}}
+}

dsl/src/dsl_type.rs

@@ -1,51 +0,0 @@
-use crate::*;
-
-#[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)?;
-    pub const fn $seek:ident      $($_3:tt)?;
-    pub const fn $seek_start:ident  ($source1:ident) $body1:block
-    pub const fn $seek_length:ident ($source2:ident) $body2:block
-})=>{
-    pub trait $T: Dsl { $($trait)* }
-    impl<D: Dsl> $T for D {} 
-    dsl_peek_seek!($peek, $peek_only, $seek, $seek_start, $seek_length);
-    pub const fn $seek_start  ($source1: &str) -> DslPerhaps<usize> $body1
-    pub const fn $seek_length ($source2: &str) -> DslPerhaps<usize> $body2
-});
-
-#[macro_export] macro_rules! dsl_peek_seek(($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_space(source, start + length, Some("peek_only")) { 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),
-            },
-        }
-    }
-});

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>>>;
+use std::{sync::Arc, collections::BTreeMap, path::PathBuf};
 /// 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())
-        }
-    }
 }

output/src/ops.rs

@@ -511,7 +511,7 @@ transform_xy_unit!("padding/x" "padding/y" "padding/xy"|self: Padding, area|{
 
     ///// The syntagm `(when :condition :content)` corresponds to a [When] layout element.
     //impl<S, A> FromDsl<S> for When<A> where bool: FromDsl<S>, A: FromDsl<S> {
-        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExp>) -> Perhaps<Self> {
+        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExpr>) -> Perhaps<Self> {
             //source.exp_match("when", |_, tail|Ok(Some(Self(
                 //FromDsl::<S>::provide(state,
                     //tail.nth(0, ||"no condition".into())?, ||"no condition".into())?,
@@ -522,7 +522,7 @@ transform_xy_unit!("padding/x" "padding/y" "padding/xy"|self: Padding, area|{
     //}
     ///// The syntagm `(either :condition :content1 :content2)` corresponds to an [Either] layout element.
     //impl<S, A, B> FromDsl<S> for Either<A, B> where S: Eval<Ast, bool> + Eval<Ast, A> + Eval<Ast, B> {
-        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExp>) -> Perhaps<Self> {
+        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExpr>) -> Perhaps<Self> {
             //source.exp_match("either", |_, tail|Ok(Some(Self(
                 //state.eval(tail.nth(0, ||"no condition")?, ||"no condition")?,
                 //state.eval(tail.nth(1, ||"no content 1")?, ||"no content 1")?,
@@ -533,7 +533,7 @@ transform_xy_unit!("padding/x" "padding/y" "padding/xy"|self: Padding, area|{
     ///// The syntagm `(align/* :content)` corresponds to an [Align] layout element,
     ///// where `*` specifies the direction of the alignment.
     //impl<S, A> FromDsl<S> for Align<A> where S: Eval<Option<Ast>, A> {
-        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExp>) -> Perhaps<Self> {
+        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExpr>) -> Perhaps<Self> {
             //source.exp_match("align/", |head, tail|Ok(Some(match head {
                 //"c"  => Self::c(state.eval(tail.nth(0,  ||"no content")?, ||"no content")),
                 //"x"  => Self::x(state.eval(tail.nth(0,  ||"no content")?, ||"no content")),
@@ -553,7 +553,7 @@ transform_xy_unit!("padding/x" "padding/y" "padding/xy"|self: Padding, area|{
     ///// The syntagm `(bsp/* :content1 :content2)` corresponds to a [Bsp] layout element,
     ///// where `*` specifies the direction of the split.
     //impl<S, A, B> FromDsl<S> for Bsp<A, B> where S: Eval<Option<Ast>, A> + Eval<Option<Ast>, B> {
-        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExp>) -> Perhaps<Self> {
+        //fn try_provide (state: &S, source: &DslVal<impl DslStr, impl DslExpr>) -> Perhaps<Self> {
             //source.exp_match("bsp/", |head, tail|Ok(Some(match head {
                 //"n" => Self::n(tail.nth(0, ||"no content 1"), tail.nth(1, ||"no content 2")),
                 //"s" => Self::s(tail.nth(0, ||"no content 1"), tail.nth(1, ||"no content 2")),

proc/src/proc_expose.rs

@@ -90,7 +90,7 @@ impl ExposeImpl {
                         match dsl.key()? {
                             Some("true")  => Ok(Some(true)),
                             Some("false") => Ok(Some(false)),
-                            _ => match dsl.sym()? { #(#variants)* _ => Ok(None) }
+                            _ => match dsl.word()? { #(#variants)* _ => Ok(None) }
                         }
                     }
                 }
@@ -102,7 +102,7 @@ impl ExposeImpl {
                     fn from_dsl (state: &#state, dsl: &impl Dsl) -> Perhaps<Self> {
                         match dsl.num()? {
                             Some(n) => Ok(Some(n.parse::<#t>()?)),
-                            _ => match dsl.sym()? { #(#variants)* _ => Ok(None) }
+                            _ => match dsl.word()? { #(#variants)* _ => Ok(None) }
                         }
                     }
                 }
@@ -112,7 +112,7 @@ impl ExposeImpl {
                 /// Generated by [tengri_proc::expose].
                 impl ::tengri::dsl::FromDsl<#state> for #t {
                     fn from_dsl (state: &#state, dsl: &impl Dsl) -> Perhaps<Self> {
-                        match dsl.sym()? { #(#variants)* _ => Ok(None) }
+                        match dsl.word()? { #(#variants)* _ => Ok(None) }
                     }
                 }
             }

tui/src/tui_engine/tui_event.rs

@@ -18,14 +18,14 @@ pub struct TuiKey(Option<KeyCode>, KeyModifiers);
 impl TuiKey {
     const SPLIT: char = '/';
     pub fn from_dsl (dsl: impl Dsl) -> Usually<Self> {
-        if let Some(symbol) = dsl.sym()? {
-            let symbol = symbol.trim();
-            Ok(if symbol == ":char" {
+        if let Some(word) = dsl.word()? {
+            let word = word.trim();
+            Ok(if word == ":char" {
                 Self(None, KeyModifiers::NONE)
-            } else if symbol.chars().nth(0) == Some('@') {
+            } else if word.chars().nth(0) == Some('@') {
                 let mut key       = None;
                 let mut modifiers = KeyModifiers::NONE;
-                let mut tokens    = symbol[1..].split(Self::SPLIT).peekable();
+                let mut tokens    = word[1..].split(Self::SPLIT).peekable();
                 while let Some(token) = tokens.next() {
                     if tokens.peek().is_some() {
                         match token {
@@ -47,7 +47,7 @@ impl TuiKey {
                 }
                 Self(key, modifiers)
             } else {
-                return Err(format!("TuiKey: unexpected: {symbol}").into())
+                return Err(format!("TuiKey: unexpected: {word}").into())
             })
         } else {
             return Err(format!("TuiKey: unspecified").into())