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use std::str::FromStr;
use pest::iterators::Pair;
use pest::prec_climber::{Assoc, Operator, PrecClimber};
use pest::Parser;
use yolol_number::YololNumber;
use crate::ast::{InfixOp, PrefixOp, YolkNode};
use crate::error::ParseError;
#[cfg(test)]
mod tests;
lazy_static! {
static ref PREC_CLIMBER: PrecClimber<Rule> = build_prec_climber();
}
fn build_prec_climber() -> PrecClimber<Rule> {
PrecClimber::new(vec![
Operator::new(Rule::logical_or, Assoc::Left),
Operator::new(Rule::logical_and, Assoc::Left),
Operator::new(Rule::equal, Assoc::Left) | Operator::new(Rule::not_equal, Assoc::Left),
Operator::new(Rule::less_than, Assoc::Left)
| Operator::new(Rule::less_equal, Assoc::Left)
| Operator::new(Rule::greater_than, Assoc::Left)
| Operator::new(Rule::greater_equal, Assoc::Left),
Operator::new(Rule::plus, Assoc::Left) | Operator::new(Rule::minus, Assoc::Left),
Operator::new(Rule::multiply, Assoc::Left)
| Operator::new(Rule::divide, Assoc::Left)
| Operator::new(Rule::modulo, Assoc::Left),
Operator::new(Rule::exponent, Assoc::Right),
])
}
#[derive(Parser)]
#[grammar = "grammar/yolk.pest"]
pub struct YolkParser;
pub fn parse(source: &str) -> Result<Vec<YolkNode>, ParseError> {
let mut ast = vec![];
let pairs = YolkParser::parse(Rule::program, source)
.map_err(|e| ParseError::BadSyntax(e.to_string()))?;
for pair in pairs {
match pair.as_rule() {
Rule::import_stmt => ast.push(parse_import_stmt(pair)),
Rule::define_stmt => ast.push(parse_define_stmt(pair)),
Rule::let_stmt => ast.push(parse_let_stmt(pair)),
Rule::export_stmt => ast.push(parse_export_stmt(pair)),
Rule::comment => (),
Rule::EOI => (),
_ => panic!("expected rule statement, but got: {:?}", pair),
}
}
Ok(ast)
}
fn parse_import_stmt(stmt: Pair<Rule>) -> YolkNode {
let mut pairs = stmt.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
YolkNode::ImportStmt {
ident: ident.as_str().to_string(),
}
}
fn parse_define_stmt(stmt: Pair<Rule>) -> YolkNode {
let mut pairs = stmt.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
let params = pairs.next().expect("failed to unwrap params from pair");
let body = pairs.next().expect("failed to unwrap body from pair");
YolkNode::DefineStmt {
ident: ident.as_str().to_string(),
params: params
.into_inner()
.map(|x| x.as_str().to_string())
.collect(),
body: Box::new(parse_expr(body)),
}
}
fn parse_let_stmt(stmt: Pair<Rule>) -> YolkNode {
let mut pairs = stmt.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
let expr = pairs.next().expect("failed to unwrap expr from pair");
YolkNode::LetStmt {
ident: ident.as_str().to_string(),
expr: Box::new(parse_expr(expr)),
}
}
fn parse_export_stmt(stmt: Pair<Rule>) -> YolkNode {
let mut pairs = stmt.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
YolkNode::ExportStmt {
ident: ident.as_str().to_string(),
}
}
fn parse_expr(expr: Pair<Rule>) -> YolkNode {
match expr.as_rule() {
Rule::prefix_expr => {
let mut pairs = expr.into_inner();
let op = pairs.next().expect("failed to unwrap op from pair");
let expr = pairs.next().expect("failed to unwrap expr from pair");
YolkNode::PrefixExpr {
op: match op.as_rule() {
Rule::logical_not => PrefixOp::Not,
Rule::abs => PrefixOp::Abs,
Rule::sqrt => PrefixOp::Sqrt,
Rule::sin => PrefixOp::Sin,
Rule::cos => PrefixOp::Cos,
Rule::tan => PrefixOp::Tan,
Rule::asin => PrefixOp::Asin,
Rule::acos => PrefixOp::Acos,
Rule::atan => PrefixOp::Atan,
_ => panic!("expected prefix op, but got: {:?}", op),
},
expr: Box::new(parse_expr(expr)),
}
}
Rule::builtin_expr => {
let mut pairs = expr.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
let args = pairs.next().expect("failed to unwrap args from pair");
YolkNode::BuiltinExpr {
ident: ident.as_str().to_string(),
args: args.into_inner().map(parse_expr).collect(),
}
}
Rule::call_expr => {
let mut pairs = expr.into_inner();
let ident = pairs.next().expect("failed to unwrap ident from pair");
let args = pairs.next().expect("failed to unwrap args from pair");
YolkNode::CallExpr {
ident: ident.as_str().to_string(),
args: args.into_inner().map(parse_expr).collect(),
}
}
Rule::infix_expr => PREC_CLIMBER.climb(
expr.into_inner(),
|pair: Pair<Rule>| parse_expr(pair),
|lhs: YolkNode, op: Pair<Rule>, rhs: YolkNode| YolkNode::InfixExpr {
lhs: Box::new(lhs),
op: match op.as_rule() {
Rule::plus => InfixOp::Add,
Rule::minus => InfixOp::Sub,
Rule::multiply => InfixOp::Mul,
Rule::divide => InfixOp::Div,
Rule::modulo => InfixOp::Mod,
Rule::exponent => InfixOp::Exp,
Rule::less_than => InfixOp::LessThan,
Rule::less_equal => InfixOp::LessEqual,
Rule::greater_than => InfixOp::GreaterThan,
Rule::greater_equal => InfixOp::GreaterEqual,
Rule::equal => InfixOp::Equal,
Rule::not_equal => InfixOp::NotEqual,
Rule::logical_and => InfixOp::And,
Rule::logical_or => InfixOp::Or,
_ => panic!("expected infix op, but got: {:?}", op),
},
rhs: Box::new(rhs),
},
),
Rule::ident => YolkNode::Ident(expr.as_str().to_string()),
Rule::literal => YolkNode::Literal(
YololNumber::from_str(expr.as_str())
.unwrap_or_else(|e| panic!("failed to parse YololNumber from string: {}", e)),
),
Rule::array => {
let exprs: Vec<YolkNode> = expr.into_inner().map(parse_expr).collect();
YolkNode::Array(exprs)
}
_ => panic!("expected rule expression, but got: {:?}", expr),
}
}