docs and defs

Cargo.lock

@@ -31,9 +31,9 @@ checksum = "8f68f53c83ab957f72c32642f3868eec03eb974d1fb82e453128456482613d36"
 
 [[package]]
 name = "bumpalo"
-version = "3.16.0"
+version = "3.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
+checksum = "1628fb46dfa0b37568d12e5edd512553eccf6a22a78e8bde00bb4aed84d5bdbf"
 
 [[package]]
 name = "byteorder"
@@ -55,9 +55,9 @@ checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 
 [[package]]
 name = "clap"
-version = "4.5.26"
+version = "4.5.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a8eb5e908ef3a6efbe1ed62520fb7287959888c88485abe072543190ecc66783"
+checksum = "3e77c3243bd94243c03672cb5154667347c457ca271254724f9f393aee1c05ff"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -65,9 +65,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.26"
+version = "4.5.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96b01801b5fc6a0a232407abc821660c9c6d25a1cafc0d4f85f29fb8d9afc121"
+checksum = "1b26884eb4b57140e4d2d93652abfa49498b938b3c9179f9fc487b0acc3edad7"
 dependencies = [
  "anstyle",
  "clap_lex",
@@ -75,9 +75,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.5.24"
+version = "4.5.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54b755194d6389280185988721fffba69495eed5ee9feeee9a599b53db80318c"
+checksum = "bf4ced95c6f4a675af3da73304b9ac4ed991640c36374e4b46795c49e17cf1ed"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -410,9 +410,9 @@ checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
 
 [[package]]
 name = "rustix"
-version = "0.38.43"
+version = "0.38.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a78891ee6bf2340288408954ac787aa063d8e8817e9f53abb37c695c6d834ef6"
+checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
 dependencies = [
  "bitflags",
  "errno",
@@ -457,9 +457,9 @@ checksum = "3c5e1a9a646d36c3599cd173a41282daf47c44583ad367b8e6837255952e5c67"
 
 [[package]]
 name = "syn"
-version = "2.0.96"
+version = "2.0.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d5d0adab1ae378d7f53bdebc67a39f1f151407ef230f0ce2883572f5d8985c80"
+checksum = "36147f1a48ae0ec2b5b3bc5b537d267457555a10dc06f3dbc8cb11ba3006d3b1"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -519,9 +519,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.14"
+version = "1.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "adb9e6ca4f869e1180728b7950e35922a7fc6397f7b641499e8f3ef06e50dc83"
+checksum = "a210d160f08b701c8721ba1c726c11662f877ea6b7094007e1ca9a1041945034"
 
 [[package]]
 name = "unicode-segmentation"

docs/src/SUMMARY.md

@@ -10,7 +10,6 @@
 
 - [Arithmetic](./lang/arithmetic.md)
     - [Bitwise operators](./lang/bitwise.md)
-    - [Operators reference](./lang/operators.md)
 - [Variables and scope](./lang/variables.md)
 - [Functions](./lang/functions.md)
     - [Partial functions and pipes](./lang/partial.md)
@@ -21,5 +20,8 @@
 - [Iterators](./lang/iterators.md)
     - [Ranges](./lang/ranges.md)
 - [Exceptions](./lang/exceptions.md)
+- [Language reference](./lang/reference.md)
+    - [Grammar](./lang/grammar.md)
+    - [Operators reference](./lang/operators.md)
 
 

docs/src/lang/grammar.md

@@ -0,0 +1,95 @@
+# Grammar
+
+Some additional restrictions, such as the precedence of operators or the kinds
+of expressions that are valid to assign to, are not represented here. See the
+[operators reference](operators.md) for a description of operator precedence.
+
+```grammar
+program := block EOF
+
+# LINESEP: either a semicolon or newline
+block := LINESEP* (expr LINESEP+)* expr?
+
+expr := assign
+      | return assign?
+      | break assign?
+      | continue
+
+assign := pipeline | pipeline assign_op assign
+
+assign_op := "=" | "++=" | "&=" | "#|=" | "#^=" | "#&=" | "<<=" | ">>=" | "+="
+           | "-=" | "*=" | "/=" | "//=" | "%=" | "^="
+
+pipeline := lambda | pipeline "|" lambda
+
+lambda := prec_expr
+        | "\" ident_list "->" lambda
+        | "&" lambda
+
+# See the operators reference
+prec_expr := access
+           | prec_expr infix_op prec_expr
+           | prec_expr postfix_op
+           | prefix_op prec_expr
+
+infix_op := "==" | "!=" | ">" | ">=" | "<" | "<=" | "++" | "&" | ".." | "..="
+          | "#|" | "#^" | "#&" | "<<" | ">>" | "+" | "-" | "*" | "/" | "//"
+          | "%" | "^" | "and" | "or"
+
+prefix_op := "-" | "!" | "~" | "*.." | "*..="
+
+postfix_op := "..*"
+
+access := term access_op*
+access_op := "(" expr_list ")"
+           | "[" expr "]"
+           | "." IDENT
+           | "->" IDENT "(" expr_list ")"
+
+var := term
+     | "global" IDENT
+     | "var" IDENT
+     | fn_decl
+fn_decl := "fn" IDENT? "(" ident_list ")" fn_body
+fn_body := "do" block "end"
+         | "=" expr
+
+term := IDENT
+      | "(" expr ")"
+      | "[" list_items "]"
+      | "{" table_items "}"
+      | "$"
+      | "do" block "end"
+      | "if" if_stmt_chain
+      | "while" expr "do" block "end"
+      | "for" IDENT "in" expr "do" block "end"
+      | "try" block catch_block* "end"
+      | INTEGER
+      | FLOAT
+      | IMAGINARY
+      | STRING
+      | SYMBOL
+      | "true"
+      | "false"
+      | "nil"
+      | "*..*"
+
+if_stmt_chain := expr "then" block if_stmt_end
+if_stmt_end := "elif" if_stmt_chain
+             | "else" block "end"
+             | "end"
+
+catch_block := "catch" ("*" | symbol_list) ("in" IDENT)? "do" block
+symbol_list := (SYMBOL ",")* SYMBOL?
+
+ident_list := (IDENT ",")* IDENT?
+
+expr_list := (expr ",")* expr?
+
+list_items := (list_item ",")* list_item?
+list_item := ".."? expr
+
+table_items := (table_item ",")* table_item?
+table_item := ".." expr
+            | term "=" expr
+```

docs/src/lang/lists.md

@@ -4,7 +4,8 @@ Lists in Talc are written as comma-separated items between square brackets.
 Lists may be *heterogeneous* (contain items of different types). Similarly to
 strings, lists may be concatenated using `++`. Lists can be indexed by writing
 the index in square brackets after the list. The first element of the list is
-at index zero.
+at index zero. The `&` operator will add a single element to the end of a list,
+returning a new list.
 
 ```talc
 >> numbers = [1, 5, 6, 4, 2, 3]
@@ -13,6 +14,15 @@ at index zero.
 4
 >> numbers ++ [8, 9]
 [1, 5, 6, 4, 2, 3, 8, 9]
+>> numbers & 7
+[1, 5, 6, 4, 2, 3, 7]
+```
+
+Lists are heterogeneous, so they may contain values of different types.
+
+```talc
+>> things = [1, 2.0, "three", 4/1, :five]
+[1, 2.0, "three", 4/1, :five]
 ```
 
 Lists are *mutable* and their elements can be assigned to or modified.
@@ -46,3 +56,69 @@ ranges further in their own chapter.
 >> squares[*..-3]
 [0, 1, 4, 9, 16]
 ```
+
+## Interpolation
+
+Using the `..` operator, a list can be created by combining the elements from
+multiple different collections
+
+```talc
+>> even = [2, 4, 6, 8]
+[2, 4, 6, 8]
+>> odd = [1, 3, 5, 7, ..even]
+[1, 3, 5, 7, 2, 4, 6, 8]
+>> n = [1, ..[2, 3, 4], 5, ..[6, ..[7, 8]], ..[9]]
+[1, 2, 3, 4, 5, 6, 7, 8, 9]
+```
+
+Any iterator or iterable value can be used
+
+```talc
+>> squares = [..(0..10 | map(\x -> x*x))]
+[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
+```
+
+## Destructuring
+
+A list can be destructured in an assignment expression as follows:
+
+```talc
+>> vals = [6, 2, 8]
+[6, 2, 8]
+>> [a, b, c] = vals
+[6, 2, 8]
+>> a
+6
+>> b
+2
+>> c
+8
+```
+
+If the number of elements in the list does not match the number in the
+destructure, an error is thrown.
+
+A single interpolation may also be used to collect all remaining values. The
+interpolation may occur in the beginning, middle, or end of the assignment.
+
+```talc
+>> ns = [1, 2, 3, 4, 5]
+[1, 2, 3, 4, 5]
+>> [a, b, ..rest] = ns
+[1, 2, 3, 4, 5]
+>> a
+1
+>> b
+2
+>> rest
+[3, 4, 5]
+>> [a, ..middle, z] = ns
+[1, 2, 3, 4, 5]
+>> a
+1
+>> middle
+[2, 3, 4]
+>> rest
+5
+```
+

docs/src/lang/reference.md

@@ -0,0 +1,4 @@
+# Language reference
+
+These pages present a more thorough (and less guided) description of the
+Talc language.

docs/theme/highlight.js

@@ -105,3 +105,35 @@ hljs.registerLanguage('talc', function() {
 		]
 	}
 })
+
+hljs.registerLanguage('grammar', function() {
+	const STR_RE = "'[^']*'|\"[^\"]*\"";
+	const TERMINAL_RE = "\\b[A-Z_]+\\b"
+	const OP_RE = ":=|\\||\\+|\\*|\\?|\\(|\\)"
+
+	return {
+		name: "Grammar",
+		contains: [
+			{
+				className: 'string',
+				begin: STR_RE,
+				relevance: 0
+			},
+			{
+				className: 'variable',
+				begin: TERMINAL_RE,
+				relevance: 0
+			},
+			{
+				className: 'literal',
+				begin: OP_RE,
+				relevance: 0
+			},
+			hljs.COMMENT(
+				'#', // begin
+				'\n', // end
+				{}
+			)
+		]
+	}
+})

talc-lang/src/parser/parser.rs

@@ -272,8 +272,15 @@ impl<'s> Parser<'s> {
 					let ext = self.parse_expr()?;
 					items.push(TableItem::Interpolate(b(ext)));
 				}
-				k if k.expr_first() => {
+				T::True
-					let key = self.parse_term_not_ident()?;
+				| T::False
+				| T::Nil
+				| T::Dollar
+				| T::Integer
+				| T::String
+				| T::Symbol
+				| T::LParen => {
+					let key = self.parse_term()?;
 					expect!(self, T::Equal);
 					let value = self.parse_expr()?;
 					items.push(TableItem::Pair(b(key), b(value)));
@@ -399,9 +406,10 @@ impl<'s> Parser<'s> {
 		}
 	}
 
-	fn parse_term_not_ident(&mut self) -> Result<Expr> {
+	fn parse_term(&mut self) -> Result<Expr> {
 		let tok = self.next()?;
 		match tok.kind {
+			T::Identifier => Ok(E::Ident(Symbol::get(tok.content)).span(tok.span)),
 			T::LParen => {
 				let e = self.parse_expr()?;
 				expect!(self, T::RParen);
@@ -485,26 +493,46 @@ impl<'s> Parser<'s> {
 		}
 	}
 
-	fn parse_term(&mut self) -> Result<Expr> {
+	fn parse_fn_decl(&mut self) -> Result<Expr> {
-		let Some(tok) = try_next!(self, T::Identifier | T::Var | T::Global) else {
+		let tok_fn = expect!(self, T::Fn);
-			return self.parse_term_not_ident()
+		let name = try_next!(self, T::Identifier).map(|t| Symbol::get(t.content));
-		};
+		expect!(self, T::LParen);
-		match tok.kind {
+		let args = self.parse_ident_list()?;
-			T::Identifier => Ok(E::Ident(Symbol::get(tok.content)).span(tok.span)),
+		expect!(self, T::RParen);
+		match expect!(self, T::Do | T::Equal).kind {
+			T::Do => {
+				let content = self.parse_block()?;
+				let end = expect!(self, T::End);
+				Ok(E::FnDef(name, args, b(content)).span(tok_fn.span + end.span))
+			}
+			T::Equal => {
+				let content = self.parse_expr()?;
+				let span = tok_fn.span + content.span;
+				Ok(E::FnDef(name, args, b(content)).span(span))
+			}
+			_ => unreachable!("parse_fn_decl: guaranteed by try_next!"),
+		}
+	}
+
+	fn parse_var(&mut self) -> Result<Expr> {
+		match self.peek()?.kind {
 			T::Global => {
+				let tok = self.next()?;
 				let ident = expect!(self, T::Identifier);
 				Ok(E::Global(Symbol::get(ident.content)).span(tok.span + ident.span))
 			}
 			T::Var => {
+				let tok = self.next()?;
 				let ident = expect!(self, T::Identifier);
 				Ok(E::Var(Symbol::get(ident.content)).span(tok.span + ident.span))
 			}
-			_ => unreachable!("guarenteed by try_next"),
+			T::Fn => self.parse_fn_decl(),
+			_ => self.parse_term(),
 		}
 	}
 
 	fn parse_access(&mut self) -> Result<Expr> {
-		let mut lhs = self.parse_term()?;
+		let mut lhs = self.parse_var()?;
 		loop {
 			let tok = try_next!(self, T::LParen | T::LBrack | T::Arrow | T::Dot);
 			match tok.map(|t| t.kind) {
@@ -651,7 +679,7 @@ impl<'s> Parser<'s> {
 		if let Some(op) = self.peek()?.kind.assign_op() {
 			let lval = LValue::from_expr(lhs)?;
 			self.next()?;
-			let rhs = self.parse_decl()?;
+			let rhs = self.parse_assign()?;
 			let rhs_span = rhs.span;
 			Ok(E::Assign(op, b(lval), b(rhs)).span(lhs_span + rhs_span))
 		} else {
@@ -659,41 +687,12 @@ impl<'s> Parser<'s> {
 		}
 	}
 
-	fn parse_fn_decl(&mut self) -> Result<Expr> {
-		let tok_fn = expect!(self, T::Fn);
-		let name = try_next!(self, T::Identifier).map(|t| Symbol::get(t.content));
-		expect!(self, T::LParen);
-		let args = self.parse_ident_list()?;
-		expect!(self, T::RParen);
-		match expect!(self, T::Do | T::Equal).kind {
-			T::Do => {
-				let content = self.parse_block()?;
-				let end = expect!(self, T::End);
-				Ok(E::FnDef(name, args, b(content)).span(tok_fn.span + end.span))
-			}
-			T::Equal => {
-				let content = self.parse_expr()?;
-				let span = tok_fn.span + content.span;
-				Ok(E::FnDef(name, args, b(content)).span(span))
-			}
-			_ => unreachable!("parse_fn_decl: guaranteed by try_next!"),
-		}
-	}
-
-	fn parse_decl(&mut self) -> Result<Expr> {
-		match self.peek()?.kind {
-			T::Fn => self.parse_fn_decl(),
-			_ => self.parse_assign(),
-		}
-	}
-
 	fn parse_expr(&mut self) -> Result<Expr> {
-		let tok = try_next!(self, T::Return | T::Break | T::Continue);
+		match self.peek()?.kind {
-		if let Some(tok) = tok {
-			match tok.kind {
 			T::Return => {
+				let tok = self.next()?;
 				if self.peek()?.kind.expr_first() {
-						let expr = self.parse_decl()?;
+					let expr = self.parse_assign()?;
 					let span = expr.span;
 					Ok(E::Return(Some(b(expr))).span(tok.span + span))
 				} else {
@@ -701,19 +700,20 @@ impl<'s> Parser<'s> {
 				}
 			}
 			T::Break => {
+				let tok = self.next()?;
 				if self.peek()?.kind.expr_first() {
-						let expr = self.parse_decl()?;
+					let expr = self.parse_assign()?;
 					let span = expr.span;
 					Ok(E::Break(Some(b(expr))).span(tok.span + span))
 				} else {
 					Ok(E::Break(None).span(tok.span))
 				}
 			}
-				T::Continue => Ok(E::Continue.span(tok.span)),
+			T::Continue => {
-				_ => unreachable!("parse_expr: guaranteed by try_next!"),
+				let tok = self.next()?;
+				Ok(E::Continue.span(tok.span))
 			}
-		} else {
+			_ => self.parse_assign(),
-			self.parse_decl()
 		}
 	}