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-rw-r--r--src/parser.rs96
1 files changed, 92 insertions, 4 deletions
diff --git a/src/parser.rs b/src/parser.rs
index 79e9ec8..2cb2734 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -27,7 +27,7 @@ pub fn parse_file(path: &str) -> Vec<Expression> {
/// Parses a lambda-calculus-like language into an AST.
pub fn parse_lambda(input: &str) -> Result<Expression, peg::error::ParseError<peg::str::LineCol>> {
// this is kinda awful, i miss my simple nim pegs
- peg::parser!{
+ peg::parser! {
grammar lambda() for str {
rule identifier() -> String
= i:['a'..='z' | 'A'..='Z' | '0'..='9']+ {
@@ -121,10 +121,11 @@ pub fn lex(input: &str) -> Result<String, &'static str> {
level: usize, // current indentation level
count: usize, // current whitespace count
previous: Previous,
+ comment: bool // is the current line a comment?
}
let indent_size: usize = 2;
- let mut state = State { blank: true, level: 0, count: 0, previous: Previous::Start };
+ let mut state = State { blank: true, level: 0, count: 0, previous: Previous::Start, comment: false };
let mut buffer = String::new();
let mut result = String::new();
@@ -169,6 +170,7 @@ pub fn lex(input: &str) -> Result<String, &'static str> {
result.push_str(&buffer);
state.count = 0;
+ state.comment = false;
buffer.clear();
}
state.blank = true;
@@ -176,11 +178,17 @@ pub fn lex(input: &str) -> Result<String, &'static str> {
' ' if state.blank => {
state.count += 1;
},
+ '#' => {
+ state.blank = false;
+ state.comment = true;
+ },
_ => {
if state.blank {
state.blank = false;
}
- buffer.push(c);
+ if !state.comment {
+ buffer.push(c);
+ }
},
}
}
@@ -200,5 +208,85 @@ pub fn lex(input: &str) -> Result<String, &'static str> {
/// The lex() function can turn an indentation-based language into a language recognizable by this.
#[allow(unused_variables)]
pub fn parse_lang(input: &str) -> Result<Vec<Expression>, peg::error::ParseError<peg::str::LineCol>> {
- todo!();
+ peg::parser! {
+ grammar puck() for str {
+ // whitespace
+ rule w() = ("\n" / " ")+
+ // identifiers
+ rule ident() -> String = i:['a'..='z' | 'A'..='Z' | '0'..='9']+ {
+ i.iter().collect::<String>()
+ }
+ // constants
+ rule cons() -> Expression = p:"-"? c:['0'..='9']+ {
+ let value = c.iter().collect::<String>().parse::<Value>().unwrap();
+ Expression::Constant {
+ term: Term {
+ val: if let Some(_) = p {
+ value.wrapping_neg()
+ } else {
+ value
+ },
+ kind: Type::Empty
+ }
+ }
+ }
+ // types
+ // still fucking awful
+ rule empty() -> Type = k:"empty" {Type::Empty}
+ rule unit() -> Type = k:"unit" {Type::Unit}
+ rule boolean() -> Type = k:"bool" {Type::Boolean}
+ rule natural() -> Type = k:"nat" {Type::Natural}
+ rule integer() -> Type = k:"int" {Type::Integer}
+ rule function() -> Type = f:kind() w() "->" w() t:kind() {
+ Type::Function { from: Box::new(f), to: Box::new(t) }
+ }
+ rule kind() -> Type
+ = k:(empty() / unit() / boolean() / natural() / integer()) {
+ k
+ }
+ rule ann() -> Expression
+ = e:(cond() / abs() / app() / cons() / var()) w() ":" w() k:kind() {
+ Expression::Annotation {
+ expr: Box::new(e),
+ kind: k
+ }
+ }
+ rule var() -> Expression
+ = v:ident() {
+ Expression::Variable {
+ id: v
+ }
+ }
+ rule abs() -> Expression
+ = "func" "(" p:ident() ")" w() k:function() w() "=" w() "{" f:expr() "}" {
+ Expression::Annotation {
+ expr: Box::new(Expression::Abstraction { param: p, func: Box::new(f) }),
+ kind: k
+ }
+ }
+ // fixme: this requires, uh, refactoring the ast...
+ rule app() -> Expression
+ = f:ident() "(" a:expr() ")" {
+ Expression::Application {
+ func: Box::new(Expression::Variable { id: f }),
+ arg: Box::new(a)
+ }
+ }
+ rule cond() -> Expression
+ = "if" w() c:expr() w() ":" w() "{" w() t:expr() w() "}" w() "else:" w() "{" w() e:expr() w() "}" {
+ Expression::Conditional {
+ if_cond: Box::new(c),
+ if_then: Box::new(t),
+ if_else: Box::new(e)
+ }
+ }
+ pub rule expr() -> Expression
+ = w()? e:(cond()) w()? {
+ e
+ }
+ pub rule file() -> Vec<Expression>
+ = expr() ++ w()
+ }
+ }
+ return puck::file(input);
}