dsl: testing expression handling

dsl/README.md

@@ -92,3 +92,23 @@ 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)`              |E0 |`a b c`|`(a b c)`|none           |
+|`(a b c) d e f`        |E0 |E2     |`(a b c)`|`d e f`        |
+|`a (b c d) e f`        |E2 |E0     |`a`      |`(b c d) e f`  |
+
+* **E0**: Expected `(`
+* **E1**: Unexpected `(`
+* **E2**: Trailing characters

dsl/src/dsl.rs

@@ -8,7 +8,8 @@ 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 konst::iter::for_each;
+pub(crate) use konst::string::{str_from, str_range, char_indices};
 pub(crate) use thiserror::Error;
 pub(crate) use ::tengri_core::*;
 pub(crate) use self::DslError::*;
@@ -16,77 +17,52 @@ 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 {
+    fn src (&self) -> DslPerhaps<&str> { unreachable!("Dsl::src default impl") }
-        unreachable!("Dsl::src default impl")
-    }
 });
 impl Dsl for Arc<str> {
-    fn src (&self) -> &str { self.as_ref() }
+    fn src (&self) -> DslPerhaps<&str> { Ok(Some(self.as_ref())) }
 }
 impl<'s> Dsl for &'s str {
-    fn src (&self) -> &str { self.as_ref() }
+    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> Dsl for Result<D, DslError> {
+    fn src (&self) -> DslPerhaps<&str> {
+        match self { Ok(dsl) => Ok(dsl.src()?), Err(e) => Err(*e) }
+    }
 }
-
 impl<D: Dsl> DslExp for D {}
 pub trait DslExp: Dsl {
-    fn exp (&self) -> DslPerhaps<&str> {
+    fn exp  (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(exp_peek_inner)) }
-        Ok(exp_peek(self.src())?)
+    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()))) }
-    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> DslSym for D {}
 pub trait DslSym: Dsl {
-    fn sym (&self) -> DslPerhaps<&str> { crate::parse::sym_peek(self.src()) }
+    fn sym (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(sym_peek_only)) }
 }
-
 impl<D: Dsl> DslKey for D {}
 pub trait DslKey: Dsl {
-    fn key (&self) -> DslPerhaps<&str> { crate::parse::key_peek(self.src()) }
+    fn key (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(key_peek_only)) }
 }
-
 impl<D: Dsl> DslText for D {}
 pub trait DslText: Dsl {
-    fn text (&self) -> DslPerhaps<&str> { crate::parse::text_peek(self.src()) }
+    fn text (&self) -> DslPerhaps<&str> { ok_flat(self.src()?.map(text_peek_only)) }
 }
-
 impl<D: Dsl> DslNum for D {}
 pub trait DslNum: Dsl {
-    fn num (&self) -> DslPerhaps<&str> { crate::parse::num_peek(self.src()) }
+    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 +73,28 @@ 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
+    }
+}

dsl/src/dsl_parse.rs

@@ -1,123 +1,172 @@
 use crate::*;
 
-macro_rules! iter_chars(($source:expr => |$i:ident, $c:ident|$val:expr)=>{
+macro_rules! def_peek_seek(($peek:ident, $peek_only:ident, $seek:ident, $seek_start:ident, $seek_length:ident)=>{
-    while let Some((($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) } }
+            Err(e) => Err(e)
+        }
+    }
+    /// 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) {
+            Ok(Some((start, length))) => {
+                let remaining = source.len().saturating_sub(start + length);
+                let tail = str_range(source, start + length, remaining);
+                for_each!((_, c) in char_indices(tail) => if !is_whitespace(c) {
+                    return Err(Unexpected(c))
+                });
+                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(start)) => match $seek_length(str_from(source, start)) {
                 Ok(Some(length)) => Ok(Some((start, length))),
                 Ok(None) => Ok(None),
                 Err(e) => Err(e),
             },
             Ok(None) => Ok(None),
-            Err(e) => Err(e) } } });
+            Err(e) => Err(e)
+        }
+    }
+});
 
-def_peek_seek!(exp_peek, exp_seek, exp_seek_start, exp_seek_length);
+pub const fn no_trailing_non_whitespace (source: &str, offset: usize) -> DslResult<()> {
-pub const fn is_exp_start (c: char) -> bool { matches!(c, '(') }
+    let tail = str_range(source, offset, source.len().saturating_sub(offset));
-pub const fn is_exp_end (c: char) -> bool { matches!(c, ')') }
+    for_each!((_, c) in char_indices(tail) => if !is_whitespace(c) {
-pub const fn exp_seek_start (mut source: &str) -> DslPerhaps<usize> {
+        return Err(Unexpected(c))
-    iter_chars!(source => |i, c| if is_exp_start(c) {
+    });
+    Ok(())
+}
+
+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) {
+                return Err(e)
+            }
+            let start = if length > 0 { 1 } else { 0 };
+            Ok(Some(str_range(source, start, start + length.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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn exp_seek_length (source: &str) -> DslPerhaps<usize> {
     let mut depth = 0;
-    iter_chars!(source => |i, c| if is_exp_start(c) {
+    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))
+            return Ok(Some(i + 1))
         } else {
             depth -= 1;
         }
     });
-    Ok(None)
+    Err(Incomplete)
 }
 
-def_peek_seek!(sym_peek,  sym_seek,  sym_seek_start,  sym_seek_length);
+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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn sym_seek_start (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_sym_start(c) {
+    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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn sym_seek_length (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_sym_end(c) {
+    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(None)
+    Ok(Some(source.len()))
 }
 
-def_peek_seek!(key_peek,  key_seek,  key_seek_start,  key_seek_length);
+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_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> {
+pub const fn key_seek_start (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_key_start(c) {
+    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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn key_seek_length (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_key_end(c) {
+    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(None)
+    Ok(Some(source.len()))
 }
 
-def_peek_seek!(text_peek, text_seek, text_seek_start, text_seek_length);
+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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn text_seek_start (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_text_start(c) {
+    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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn text_seek_length (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_text_end(c) { return Ok(Some(i)) });
+    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_seek,  num_seek_start,  num_seek_length);
+def_peek_seek!(num_peek, num_peek_only, num_seek, num_seek_start, num_seek_length);
-pub const fn num_seek_start (mut source: &str) -> DslPerhaps<usize> {
+pub const fn num_seek_start (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_digit(c) {
+    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 (mut source: &str) -> DslPerhaps<usize> {
+pub const fn num_seek_length (source: &str) -> DslPerhaps<usize> {
-    iter_chars!(source => |i, c| if is_num_end(c) {
+    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))
@@ -154,7 +203,7 @@ pub const fn peek (mut src: &str) -> DslPerhaps<&str> {
         _ 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) {
+            for_each!((i, c) in char_indices(src) => if !is_whitespace(c) {
                 return Err(Unexpected(c))
             });
             return Ok(None)
@@ -170,7 +219,7 @@ pub const fn seek (mut src: &str) -> DslPerhaps<(usize, usize)> {
         _ 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) {
+            for_each!((i, c) in char_indices(src) => if !is_whitespace(c) {
                 return Err(Unexpected(c))
             });
             return Ok(None)

dsl/src/dsl_test.rs

@@ -0,0 +1,90 @@
+use crate::*;
+macro_rules!is_ok_some(($exp:expr, $val:expr)=>{assert_eq!($exp, Ok(Some($val)))};);
+macro_rules!is_ok_none(($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_ok_some!(key_seek_start("foo"),   0);
+    is_ok_some!(key_seek_start("foo "),  0);
+    is_ok_some!(key_seek_start(" foo "), 1);
+    is_ok_some!(key_seek_length(&" foo "[1..]), 3);
+    is_ok_some!(key_seek("foo"),   (0, 3));
+    is_ok_some!(key_peek("foo"),   "foo");
+    is_ok_some!(key_seek("foo "),  (0, 3));
+    is_ok_some!(key_peek("foo "),  "foo");
+    is_ok_some!(key_seek(" foo "), (1, 3));
+    is_ok_some!(key_peek(" foo "), "foo");
+
+    is_err!("(foo)".key());
+    is_err!("foo".exp());
+
+    is_ok_some!("(foo)".exp(), "foo");
+    is_ok_some!("(foo)".head(), "(foo)");
+    is_ok_none!("(foo)".tail());
+
+    is_ok_some!("(foo bar baz)".exp(),  "foo bar baz");
+    is_ok_some!("(foo bar baz)".head(), "(foo bar baz)");
+    is_ok_none!("(foo bar baz)".tail());
+
+    is_ok_some!("(foo bar baz)".exp().head(), "foo");
+    is_ok_some!("(foo bar baz)".exp().tail(), "bar baz");
+    is_ok_some!("(foo bar baz)".exp().tail().head(), "bar");
+    is_ok_some!("(foo bar baz)".exp().tail().tail(), "baz");
+
+    is_ok_none!("foo".exp());
+    is_ok_some!("foo".key(),   "foo");
+    is_ok_some!(" foo".key(),  "foo");
+    is_ok_some!(" foo ".key(), "foo");
+
+    assert_eq!(" foo ".head(),        Ok(Some("foo")));
+    //assert_eq!(" foo ".head().head(), Ok(None));
+    assert_eq!(" foo ".head().tail(), Ok(None));
+    assert_eq!(" foo ".tail(),        Ok(None));
+    assert_eq!(" foo ".tail().head(), Ok(None));
+    assert_eq!(" foo ".tail().tail(), Ok(None));
+
+    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));
+    assert_eq!(" (foo) (bar) ".tail(),               Ok(Some("(bar)")));
+
+    assert_eq!(" (foo bar baz) ".head(),               Ok(Some("(foo bar baz)")));
+    assert_eq!(" (foo bar baz) ".head().head(),        Ok(Some("foo")));
+    assert_eq!(" (foo bar baz) ".head().tail(),        Ok(Some("bar baz")));
+    assert_eq!(" (foo bar baz) ".head().tail().head(), Ok(Some("bar")));
+    assert_eq!(" (foo bar baz) ".head().tail().tail(), Ok(Some("baz")));
+    Ok(())
+}