complete first draft of validator

src/main.rs

@@ -148,11 +148,11 @@ pub fn run(src: &'static str) {
 
     let dummy_prelude = vec![];
 
-    let mut valxor = validator::Validator::new(&ast, span, &dummy_prelude);
+    let mut v6or = validator::Validator::new(&ast, span, &dummy_prelude);
 
-    // valxor.validate();
+    v6or.validate();
 
-    // dbg!(valxor);
+    dbg!(v6or);
 
     let mut ctx = prelude();
     ctx.ast = *
@@ -167,8 +167,10 @@ pub fn run(src: &'static str) {
 
 pub fn main() {
     let src = "
-let #{:a (x, y), :b [1, 2, (a, b)]} = #{:a (1, 2), :b [1, 2, (7, 8)]}
-(x, y, a, b)
+let bar = :bar
+match :foo with {
+    :foo -> bar
+}
     ";
     run(src);
     // struct_scalpel::print_dissection_info::<value::Value>()

src/validator.rs

@@ -101,18 +101,34 @@ impl<'a> Validator<'a> {
         self.status.used_bindings.push(name);
     }
 
+    fn arity(&mut self) -> Arity {
+        let Ast::MatchClause(pattern, ..) = self.ast else {
+            unreachable!("internal Ludus error")
+        };
+        let (Ast::TuplePattern(members), _) = pattern.as_ref() else {
+            unreachable!("internal Ludus error");
+        };
+        let last_member = members.last();
+        match last_member {
+            None => Arity::Fixed(0),
+            Some((Ast::Splattern(..), _)) => Arity::Splat(members.len() as u8),
+            Some(_) => Arity::Fixed(members.len() as u8),
+        }
+    }
+
     pub fn validate(&mut self) {
+        use Ast::*;
         let root = self.ast;
         match root {
-            Ast::Error => unreachable!(),
-            Ast::Word(name) | Ast::Splat(name) => {
+            Error => unreachable!(),
+            Word(name) | Ast::Splat(name) => {
                 if !self.resolved(name) {
                     self.err(format!("unbound name `{name}`"))
                 } else {
                     self.use_name(name.to_string())
                 }
             }
-            Ast::Interpolated(parts) => {
+            Interpolated(parts) => {
                 for part in parts {
                     if let (StringPart::Word(name), span) = part {
                         self.span = *span;
@@ -129,7 +145,7 @@ impl<'a> Validator<'a> {
             // pass through tail position validation
             // check if there are any declared but undefined functions
             // pop all the bindings off the local stack
-            Ast::Block(block) => {
+            Block(block) => {
                 if block.is_empty() {
                     self.err("blocks must have at least one expression".to_string());
                     return;
@@ -160,7 +176,7 @@ impl<'a> Validator<'a> {
             }
             // if in tail position, pass through tail position validation
             // no unbound names
-            Ast::If(cond, then, r#else) => {
+            If(cond, then, r#else) => {
                 let tailpos = self.status.tail_position;
                 self.status.tail_position = false;
 
@@ -181,7 +197,7 @@ impl<'a> Validator<'a> {
                 self.span = *span;
                 self.validate();
             }
-            Ast::Tuple(members) => {
+            Tuple(members) => {
                 if members.is_empty() {
                     return;
                 }
@@ -195,7 +211,7 @@ impl<'a> Validator<'a> {
                 self.status.tail_position = tailpos;
             }
             // no more than one placeholder
-            Ast::Arguments(args) => {
+            Arguments(args) => {
                 if args.is_empty() {
                     return;
                 }
@@ -209,7 +225,7 @@ impl<'a> Validator<'a> {
                 self.status.has_placeholder = false;
                 self.status.tail_position = tailpos;
             }
-            Ast::Placeholder => {
+            Placeholder => {
                 if self.status.has_placeholder {
                     self.err(
                         "you may only use one placeholder when partially applying functions"
@@ -218,7 +234,7 @@ impl<'a> Validator<'a> {
                 }
                 self.status.has_placeholder = true;
             }
-            Ast::List(list) => {
+            List(list) => {
                 if list.is_empty() {
                     return;
                 }
@@ -232,13 +248,13 @@ impl<'a> Validator<'a> {
 
                 self.status.tail_position = tailpos;
             }
-            Ast::Pair(_, value) => {
+            Pair(_, value) => {
                 let (expr, span) = value.as_ref();
                 self.ast = expr;
                 self.span = *span;
                 self.validate();
             }
-            Ast::Dict(dict) => {
+            Dict(dict) => {
                 if dict.is_empty() {
                     return;
                 }
@@ -257,7 +273,7 @@ impl<'a> Validator<'a> {
             // then...
             // check arity is 1 if first term is keyword
             // check arity against fn info if first term is word and second term is args
-            Ast::Synthetic(first, second, rest) => {
+            Synthetic(first, second, rest) => {
                 match (&first.0, &second.0) {
                     (Ast::Word(_), Ast::Keyword(_)) => {
                         let (expr, span) = first.as_ref();
@@ -296,26 +312,32 @@ impl<'a> Validator<'a> {
                     self.validate();
                 }
             }
-            Ast::When(clauses) => {
-                // let tailpos = self.status.tail_position;
-                // for (clause, _) in clauses {
-                //     self.status.tail_position = false;
-                //     let (expr, span) = clause.cond.clone();
-                //     self.ast = &expr;
-                //     self.span = span;
-                //     self.validate();
+            WhenClause(cond, body) => {
+                let tailpos = self.status.tail_position;
+                self.status.tail_position = false;
+                let (expr, span) = cond.as_ref();
+                self.ast = expr;
+                self.span = *span;
+                self.validate();
 
-                //     self.status.tail_position = tailpos;
-                //     let (expr, span) = clause.body;
-                //     self.ast = &expr;
-                //     self.span = span;
-                //     self.validate();
-                // }
+                self.status.tail_position = tailpos;
+                let (expr, span) = body.as_ref();
+                self.ast = expr;
+                self.span = *span;
+                self.validate();
+            }
+            When(clauses) => {
+                for clause in clauses {
+                    let (expr, span) = clause;
+                    self.ast = expr;
+                    self.span = *span;
+                    self.validate();
+                }
             }
 
             // binding forms
             // TODO: set up errors to include original binding
-            Ast::LBox(name, boxed) => {
+            LBox(name, boxed) => {
                 if self.bound(name).is_some() {
                     self.err(format!("box name `{name}` is already bound"));
                 } else {
@@ -326,20 +348,52 @@ impl<'a> Validator<'a> {
                 self.span = *span;
                 self.validate();
             }
-            Ast::Let(lhs, rhs) => {
+            Let(lhs, rhs) => {
                 let (expr, span) = rhs.as_ref();
                 self.ast = expr;
                 self.span = *span;
                 self.validate();
-            }
-            Ast::Match(scrutinee, clauses) => {
-                let (expr, span) = scrutinee.as_ref();
+
+                let (expr, span) = lhs.as_ref();
                 self.ast = expr;
                 self.span = *span;
                 self.validate();
             }
+            MatchClause(pattern, guard, body) => {
+                let to = self.locals.len();
 
-            Ast::FnDeclaration(name) => {
+                let (patt, span) = pattern.as_ref();
+                self.ast = patt;
+                self.span = *span;
+                self.validate();
+
+                if let Some((expr, span)) = guard.as_ref() {
+                    self.ast = expr;
+                    self.span = *span;
+                    self.validate();
+                }
+
+                let (expr, span) = body.as_ref();
+                self.ast = expr;
+                self.span = *span;
+                self.validate();
+
+                self.locals.truncate(to);
+            }
+            Match(scrutinee, clauses) => {
+                let (expr, span) = scrutinee.as_ref();
+                self.ast = expr;
+                self.span = *span;
+                self.validate();
+
+                for clause in clauses {
+                    let (expr, span) = clause;
+                    self.ast = expr;
+                    self.span = *span;
+                    self.validate();
+                }
+            }
+            FnDeclaration(name) => {
                 let tailpos = self.status.tail_position;
                 self.status.tail_position = false;
                 if self.bound(name).is_some() {
@@ -349,7 +403,7 @@ impl<'a> Validator<'a> {
                 self.declare_fn(name.to_string());
                 self.status.tail_position = tailpos;
             }
-            Ast::Fn(name, clauses, ..) => {
+            Fn(name, clauses, ..) => {
                 match self.bound(name) {
                     Some((_, _, FnInfo::Declared)) => (),
                     None => (),
@@ -359,11 +413,16 @@ impl<'a> Validator<'a> {
                 }
 
                 let from = self.status.used_bindings.len();
-                let arities = HashSet::new();
+                let mut arities = HashSet::new();
 
                 for clause in clauses {
                     // TODO: validate all parts of clauses
+                    let (expr, span) = clause;
+                    self.ast = expr;
+                    self.span = *span;
                     // add clause arity to arities
+                    arities.insert(self.arity());
+                    self.validate();
                 }
 
                 // this should be right
@@ -381,10 +440,14 @@ impl<'a> Validator<'a> {
 
                 let info = FnInfo::Defined(arities, closed_over);
 
-                self.define_fn(name.to_string(), info)
+                let root_ptr: *const Ast = root;
+
+                self.fn_info.insert(root_ptr, info.clone());
+
+                self.define_fn(name.to_string(), info);
             }
 
-            Ast::Panic(msg) => {
+            Panic(msg) => {
                 let tailpos = self.status.tail_position;
                 self.status.tail_position = false;
                 let (expr, span) = msg.as_ref();
@@ -394,7 +457,7 @@ impl<'a> Validator<'a> {
                 self.status.tail_position = tailpos;
             }
             // TODO: fix the tail call here?
-            Ast::Do(terms) => {
+            Do(terms) => {
                 if terms.len() < 2 {
                     return self.err("do expressions must have at least two terms".to_string());
                 }
@@ -413,7 +476,7 @@ impl<'a> Validator<'a> {
                 }
                 self.validate();
             }
-            Ast::Repeat(times, body) => {
+            Repeat(times, body) => {
                 self.status.tail_position = false;
                 let (expr, span) = times.as_ref();
                 self.ast = expr;
@@ -425,7 +488,7 @@ impl<'a> Validator<'a> {
                 self.span = *span;
                 self.validate();
             }
-            Ast::Loop(with, body) => {
+            Loop(with, body) => {
                 let (expr, span) = with.as_ref();
                 self.span = *span;
                 self.ast = expr;
@@ -440,12 +503,29 @@ impl<'a> Validator<'a> {
                 self.status.in_loop = true;
                 self.status.loop_arity = input.len() as u8;
 
-                // for clause in body {}
+                for clause in body {
+                    let (expr, span) = clause;
+                    self.ast = expr;
+                    self.span = *span;
+                    match self.arity() {
+                        Arity::Fixed(clause_arity) => {
+                            if clause_arity != arity {
+                                self.err(format!("mismatched arity: expected {arity} arguments in `loop` clause; got {clause_arity}"))
+                            }
+                        }
+                        Arity::Splat(clause_arity) => {
+                            if clause_arity > arity {
+                                self.err(format!("mismathced arity: expected {arity} arguments in `loop` clause; this clause takes {clause_arity} or more"))
+                            }
+                        }
+                    };
+                    self.validate();
+                }
 
                 self.status.in_loop = in_loop;
                 self.status.loop_arity = arity;
             }
-            Ast::Recur(args) => {
+            Recur(args) => {
                 if !self.status.in_loop {
                     self.err("you may only use `recur` in a `loop` form".to_string());
                     return;
@@ -468,9 +548,86 @@ impl<'a> Validator<'a> {
                     self.validate();
                 }
             }
+            WordPattern(name) => match self.bound(name) {
+                Some((name, _span, _)) => {
+                    self.err(format!("name `{name}` is already bound"));
+                }
+                None => {
+                    self.bind(name.to_string());
+                }
+            },
+            InterpolatedPattern(parts, _) => {
+                for (part, span) in parts {
+                    if let StringPart::Word(name) = part {
+                        self.span = *span;
+                        match self.bound(name) {
+                            Some(_) => self.err(format!("name `{name}` is already bound")),
+                            None => self.bind(name.to_string()),
+                        }
+                    }
+                }
+            }
+            AsPattern(name, r#type) => {
+                match self.bound(name) {
+                    Some((name, _span, _)) => {
+                        self.err(format!("name `{name}` is already bound"));
+                    }
+                    None => {
+                        self.bind(name.to_string());
+                    }
+                }
+                let as_type = *r#type;
+                match as_type {
+                    "nil" | "bool" | "number" | "keyword" | "string" | "tuple" | "dict"
+                    | "list" | "fn" | "box" => (),
+                    _ => self.err(format!("unknown type `:{as_type}`")),
+                }
+            }
+            Splattern(splatted) => {
+                if !self.status.last_term {
+                    self.err("splats in patterns must come last".to_string());
+                }
+                match splatted.as_ref() {
+                    (Ast::Placeholder, _) => (),
+                    (Ast::Word(name), span) => match self.bound(name) {
+                        Some(_) => {
+                            self.span = *span;
+                            self.err(format!("name `{name}` is already bound"))
+                        }
+                        None => self.bind(name.to_string()),
+                    },
+                    _ => unreachable!(),
+                }
+            }
+            TuplePattern(terms) | ListPattern(terms) | DictPattern(terms) => {
+                if terms.is_empty() {
+                    return;
+                }
+                for term in terms.iter().take(terms.len() - 1) {
+                    let (patt, span) = term;
+                    self.ast = patt;
+                    self.span = *span;
+                    self.validate();
+                }
+
+                self.status.last_term = true;
+                let (patt, span) = terms.last().unwrap();
+                self.ast = patt;
+                self.span = *span;
+                self.validate();
+                self.status.last_term = false;
+            }
+            PairPattern(_, patt) => {
+                let (patt, span) = patt.as_ref();
+                self.ast = patt;
+                self.span = *span;
+                self.validate();
+            }
             // terminals can never be invalid
-            Ast::Nil | Ast::Boolean(_) | Ast::Number(_) | Ast::Keyword(_) | Ast::String(_) => (),
-            _ => todo!(),
+            Nil | Boolean(_) | Number(_) | Keyword(_) | String(_) => (),
+            // terminal patterns can never be invalid
+            NilPattern | BooleanPattern(..) | NumberPattern(..) | StringPattern(..)
+            | KeywordPattern(..) | PlaceholderPattern => (),
         };
         self.ast = root;
     }