generate action code in macro expand

src/grammar/mod.rs

@@ -1,5 +1,6 @@
 //! The grammar definition.
 
+pub mod nonce;
 pub mod parse_tree;
 pub mod repr;
 // pub mod token;

src/grammar/nonce.rs

@@ -0,0 +1,27 @@
+/*!
+
+A NONCE is just a guaranteed unique identifier. We use it to create
+persistent identity for alternatives as we transform the grammar.
+
+*/
+
+use std::cell::Cell;
+
+thread_local! {
+    static NONCE: Cell<u32> = Cell::new(0)
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+pub struct Nonce {
+    counter: u32
+}
+
+impl Nonce {
+    fn new() -> Nonce {
+        NONCE.with(|counter| {
+            let c = counter.get();
+            counter.set(c.checked_add(1).unwrap());
+            Nonce { counter: c }
+        })
+    }
+}

src/grammar/repr.rs

@@ -63,3 +63,4 @@ impl Display for TypeRepr {
         }
     }
 }
+

src/normalize/macro_expand/mod.rs

@@ -1,8 +1,10 @@
 use std::collections::{HashMap, HashSet};
 use intern::{intern, read, InternedString};
 use grammar::parse_tree::{Alternative, Condition, ConditionOp, ExprSymbol, Grammar, GrammarItem,
-                          MacroSymbol, NonterminalData, RepeatSymbol, Span, Symbol, TypeRef};
+                          MacroSymbol, NonterminalData, RepeatOp, RepeatSymbol,
+                          Span, Symbol, TypeRef};
 use normalize::{NormResult, NormError};
+use normalize::norm_util::{self, Symbols};
 use regex::Regex;
 use std::mem;
 
@@ -67,7 +69,7 @@ impl MacroExpander {
                     Symbol::Macro(msym) =>
                         items.push(try!(self.expand_macro_symbol(msym))),
                     Symbol::Expr(expr) =>
-                        items.push(self.expand_expr_symbol(expr)),
+                        items.push(try!(self.expand_expr_symbol(expr))),
                     _ =>
                         assert!(false, "don't know how to expand `{:?}`", sym)
                 }
@@ -110,6 +112,7 @@ impl MacroExpander {
                 return;
             }
             Symbol::Repeat(ref mut repeat) => {
+                // self.replace_repeat(repeat);
                 self.replace_symbol(&mut repeat.symbol);
                 return;
             }
@@ -132,6 +135,28 @@ impl MacroExpander {
         }
     }
 
+    fn replace_repeat(&mut self, repeat: &mut RepeatSymbol) {
+        match repeat.op {
+            RepeatOp::Star => {
+                // Convert X* to X+? and recurse. Annoyingly, we have
+                // to clone for this, due to not being able to move
+                // out from `&mut` pointers.
+                *repeat = RepeatSymbol {
+                    op: RepeatOp::Question,
+                    symbol: Symbol::Repeat(Box::new(RepeatSymbol {
+                        op: RepeatOp::Plus,
+                        symbol: repeat.symbol.clone()
+                    }))
+                };
+                return self.replace_repeat(repeat);
+            }
+            RepeatOp::Question |
+            RepeatOp::Plus => {
+               self.replace_symbol(&mut repeat.symbol);
+            }
+        }
+    }
+
     ///////////////////////////////////////////////////////////////////////////
     // Macro expansion
 
@@ -301,18 +326,44 @@ impl MacroExpander {
     ///////////////////////////////////////////////////////////////////////////
     // Expr expansion
 
-    fn expand_expr_symbol(&mut self, expr: ExprSymbol) -> GrammarItem {
+    fn expand_expr_symbol(&mut self, expr: ExprSymbol) -> NormResult<GrammarItem> {
         let name = intern(&expr.canonical_form());
-        GrammarItem::Nonterminal(NonterminalData {
+
+        let ty_ref = match norm_util::analyze_expr(&expr) {
+            Symbols::Named(names) => {
+                let (ex_id, ex_sym) = names[0];
+                return_err!(
+                    expr.span,
+                    "named symbols like `~{}:{}` are only allowed at the top-level of a nonterminal",
+                    ex_id, ex_sym)
+            }
+            Symbols::Anon(syms) => {
+                maybe_tuple(
+                    syms.into_iter()
+                        .cloned()
+                        .map(TypeRef::OfSymbol)
+                        .collect())
+            }
+        };
+
+        Ok(GrammarItem::Nonterminal(NonterminalData {
             span: expr.span,
             name: name,
             args: vec![],
-            type_decl: None,
+            type_decl: Some(ty_ref),
             alternatives: vec![Alternative { span: expr.span,
                                              expr: expr,
                                              condition: None,
-                                             action: None }]
-        })
+                                             action: Some(format!("(~~)")) }]
+        }))
     }
 
 }
+
+fn maybe_tuple(v: Vec<TypeRef>) -> TypeRef {
+    if v.len() == 1 {
+        v.into_iter().next().unwrap()
+    } else {
+        TypeRef::Tuple(v)
+    }
+}

src/normalize/macro_expand/test.rs

@@ -25,7 +25,7 @@ grammar Foo {
         ~v:`(~\"Id\" \",\")`* ~e:\"Id\"? =>
            v.into_iter().chain(e.into_iter()).collect();
 
-    `(~\"Id\" \",\")` = ~\"Id\" \",\";
+    `(~\"Id\" \",\")`: `\"Id\"` = ~\"Id\" \",\" => (~~);
 }
 ").unwrap();
 

src/normalize/norm_util.rs

@@ -1,5 +1,5 @@
 use intern::InternedString;
-use grammar::parse_tree::{Alternative, Symbol};
+use grammar::parse_tree::{Alternative, ExprSymbol, Symbol};
 
 #[derive(Debug)]
 pub enum AlternativeAction<'a> {
@@ -19,36 +19,36 @@ pub fn analyze_action<'a>(alt: &'a Alternative) -> AlternativeAction<'a> {
         return AlternativeAction::User(code);
     }
 
-    AlternativeAction::Default(analyze_symbols(alt))
+    AlternativeAction::Default(analyze_expr(&alt.expr))
 }
 
-pub fn analyze_symbols<'a>(alt: &'a Alternative) -> Symbols<'a> {
+pub fn analyze_expr<'a>(expr: &'a ExprSymbol) -> Symbols<'a> {
     // First look for named symbols.
     let named_symbols: Vec<_> =
-        alt.expr.symbols
-                .iter()
-                .filter_map(|sym| match *sym {
-                    Symbol::Name(id, ref sub) => Some((id, &**sub)),
-                    _ => None,
-                })
-                .collect();
+        expr.symbols
+            .iter()
+            .filter_map(|sym| match *sym {
+                Symbol::Name(id, ref sub) => Some((id, &**sub)),
+                _ => None,
+            })
+            .collect();
     if !named_symbols.is_empty() {
         return Symbols::Named(named_symbols);
     }
 
     // Otherwise, make a tuple of the items they chose with a `~`.
     let chosen_symbol_types: Vec<_> =
-        alt.expr.symbols
-                .iter()
-                .filter_map(|sym| match *sym {
-                    Symbol::Choose(..) => Some(sym),
-                    _ => None,
-                })
-                .collect();
+        expr.symbols
+            .iter()
+            .filter_map(|sym| match *sym {
+                Symbol::Choose(ref sub) => Some(&**sub),
+                _ => None,
+            })
+            .collect();
     if !chosen_symbol_types.is_empty() {
         return Symbols::Anon(chosen_symbol_types);
     }
 
     // If they didn't choose anything with a `~`, make a tuple of everything.
-    Symbols::Anon(alt.expr.symbols.iter().collect())
+    Symbols::Anon(expr.symbols.iter().collect())
 }

src/normalize/tyinfer/test.rs

@@ -2,7 +2,6 @@ use intern::intern;
 use parser;
 use normalize::macro_expand::expand_macros;
 use normalize::tyinfer::infer_types;
-use grammar::parse_tree::TypeRef;
 use grammar::repr::TypeRepr;
 
 fn type_repr(s: &str) -> TypeRepr {

src/parser/mod.rs

@@ -260,7 +260,7 @@ impl<'input> rusty_peg::Symbol<'input,Parser<'input>> for CODE {
             offset += 1; // move to next byte
         }
 
-        let regex_str = &input.text[input.offset + 1 .. offset - 1];
+        let regex_str = &input.text[input.offset .. offset];
         let output = rusty_peg::Input { text: input.text, offset: offset };
         return Ok((output, regex_str.to_string()));
     }