compiler: basic outline of the parser

1 files changed, 101 insertions, 0 deletions

diff --git a/src/parse.rs b/src/parse.rs
new file mode 100644
index 0000000..9a60863
--- /dev/null
+++ b/src/parse.rs
@@ -0,0 +1,101 @@
+use multipeek::*;
+use crate::lex::*;
+use crate::ast::Expr;
+use crate::ast::Binding::*;
+use crate::ast::Control::*;
+use crate::ast::Pattern::*;
+
+/// Convert a basic TokenStream into an AbstractSyntaxTree
+pub fn astify(input: TokenStream, name: &str) -> Result<Expr> {
+    use Token::*;
+    use Literal::*;
+    use Punctuation::*;
+
+    let mut input = multipeek(input);
+    let mut res = Vec::new();
+    while let Some(x) = input.peek() {
+        res.push(parse(&mut input, 0)?);
+    }
+    Ok(Expr::Binding(Module{ id: name.to_string(), body: res }))
+}
+
+fn parse(input: &mut MultiPeek<std::vec::IntoIter<Token>>, depth: usize) -> Result<Expr> {
+    use Token::*;
+    use Literal::*;
+    use Punctuation::*;
+    let mut input = input;
+    match input.peek() {
+        Some(Word(val)) => match val.as_str() {
+            "pub" => {
+                input.next();
+                if let Some(Word(val)) = input.peek() {
+                    match val.as_str() {
+                        "const" => parse_const(&mut input, true),
+                        "func" => parse_func(&mut input, true),
+                        "type" => parse_type(&mut input, true),
+                        "mod" => parse_mod(&mut input, true),
+                        _ => return Err("unrecognized keyword following pub".into()),
+                    }
+                } else {
+                    return Err("unrecognized thing following pub".into());
+                }
+            },
+            "let" => parse_let(&mut input),
+            "var" => parse_var(&mut input),
+            "const" => parse_const(&mut input, false),
+            "func" => parse_func(&mut input, false),
+            "type" => parse_type(&mut input, false),
+            "mod" => parse_mod(&mut input, false),
+            "from" | "import" => parse_import(&mut input),
+            "block" => parse_block(&mut input),
+            "static" => parse_static(&mut input),
+            "for" => parse_for(&mut input),
+            "while" => parse_while(&mut input),
+            "loop" => parse_loop(&mut input),
+            "if" => parse_if(&mut input),
+            "when" => parse_when(&mut input),
+            "try" => parse_try(&mut input),
+            "match" => parse_match(&mut input),
+            _ => parse_line(&mut input),
+        },
+        _ => parse_line(&mut input),
+    }
+}
+
+// Const ::= 'pub'? 'const' Pattern Annotation? '=' Expr
+fn parse_const(input: &mut MultiPeek<std::vec::IntoIter<Token>>, public: bool) -> Result<Expr> { todo!() }
+// Func ::= 'pub'? ('func' | 'proc') Ident Generics? Parameters? (':' TypeDesc) '=' Body
+fn parse_func(input: &mut MultiPeek<std::vec::IntoIter<Token>>, public: bool) -> Result<Expr> { todo!() }
+// TypeDecl ::= 'pub'? 'type' Pattern Generics? '=' 'distinct'? 'ref'? TypeDesc
+fn parse_type(input: &mut MultiPeek<std::vec::IntoIter<Token>>, public: bool) -> Result<Expr> { todo!() }
+// Mod ::= 'pub'? 'mod' Ident ':' Body
+fn parse_mod(input: &mut MultiPeek<std::vec::IntoIter<Token>>, public: bool) -> Result<Expr> { todo!() }
+
+// Let ::= 'let' Pattern Annotation? '=' Expr
+fn parse_let(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Var ::= 'var' Pattern Annotation? ('=' Expr)?
+fn parse_var(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Import ::= ('from' Ident)? 'import' Ident (',' Ident)* ('as' Ident)?
+fn parse_import(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Block ::= 'block' Ident? ':' Body
+fn parse_block(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Static ::= 'static' ':' Body
+fn parse_static(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// For ::= 'for' Pattern 'in' Expr ':' Body
+fn parse_for(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// While ::= 'while' Expr ':' Body
+fn parse_while(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Loop ::= 'loop' ':' Body
+fn parse_loop(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// If ::= 'if' Expr ':' Body ('elif' Expr ':' Body)* ('else' ':' Body)?
+fn parse_if(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// When ::= 'when' Expr ':' Body ('elif' Expr ':' Body)* ('else' ':' Body)?
+fn parse_when(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Try ::= 'try' ':' Body ('except' Ident (',' Ident)* ':' Body) ('finally' ':' Body)?
+fn parse_try(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+// Match ::= 'match' Expr ('of' Pattern (',' Pattern)* ('where' Expr)? ':' Body)+
+fn parse_match(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+
+fn parse_line(input: &mut MultiPeek<std::vec::IntoIter<Token>>) -> Result<Expr> { todo!() }
+
+// lex, parse, expand, compile?