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3 Commits

Author SHA1 Message Date
greg
a236817956 Compiler bug!??! 2019-12-15 11:58:45 -08:00
greg
b23b8ebdc7 Infrastructure for separate-object block handler
Requires one unstable feature
2019-12-15 11:56:49 -08:00
greg
8d3bbd7069 Fix annotation 2019-12-13 18:40:14 -08:00
3 changed files with 22 additions and 8 deletions

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@ -4,9 +4,11 @@ use crate::ast::*;
//TODO maybe these functions should take closures that return a KeepRecursing | StopHere type,
//or a tuple of (T, <that type>)
pub trait ASTVisitor: Sized {
pub trait ASTVisitor<BlockHandler=()>: Sized {
type BlockHandler: BlockVisitor;
fn ast(&mut self, _ast: &AST) {}
fn block(&mut self, _statements: &Vec<Statement>) {}
fn block(&mut self) -> Self::BlockHandler { Self::BlockHandler::new() }
fn block_finished(&mut self, handler: Self::BlockHandler) {}
fn statement(&mut self, _statement: &Statement) {}
fn declaration(&mut self, _declaration: &Declaration) {}
fn signature(&mut self, _signature: &Signature) {}
@ -39,3 +41,15 @@ pub trait ASTVisitor: Sized {
fn prefix_exp(&mut self, _op: &PrefixOp, _arg: &Expression) {}
fn pattern(&mut self, _pat: &Pattern) {}
}
pub trait BlockVisitor {
fn new() -> Self;
fn pre_block(&mut self) {}
fn post_block(&mut self) {}
}
impl BlockVisitor for () {
fn new() -> () { () }
}

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@ -1,7 +1,7 @@
#![allow(dead_code)]
use std::rc::Rc;
use crate::ast::*;
use crate::ast::visitor::ASTVisitor;
use crate::ast::visitor::{ASTVisitor, BlockVisitor};
use crate::util::deref_optional_box;
pub fn walk_ast<V: ASTVisitor>(v: &mut V, ast: &AST) {
@ -10,10 +10,14 @@ pub fn walk_ast<V: ASTVisitor>(v: &mut V, ast: &AST) {
}
fn walk_block<V: ASTVisitor>(v: &mut V, block: &Vec<Statement>) {
let mut block_handler = v.block();
block_handler.pre_block();
for s in block {
v.statement(s);
statement(v, s);
}
block_handler.post_block();
v.block_finished(block_handler);
}
fn statement<V: ASTVisitor>(v: &mut V, statement: &Statement) {
@ -44,7 +48,6 @@ fn declaration<V: ASTVisitor>(v: &mut V, decl: &Declaration) {
},
FuncDecl(sig, block) => {
v.signature(&sig);
v.block(&block);
walk_block(v, block);
},
TypeDecl { name, body, mutable } => v.type_declaration(name, body, *mutable),
@ -123,7 +126,6 @@ fn lambda<V: ASTVisitor>(v: &mut V, params: &Vec<FormalParam>, type_anno: Option
formal_param(v, param);
}
v.type_annotation(type_anno);
v.block(body);
walk_block(v, body);
}
@ -234,7 +236,6 @@ fn condition_arm<V: ASTVisitor>(v: &mut V, arm: &ConditionArm) {
v.expression(guard);
expression(v, guard);
});
v.block(&arm.body);
walk_block(v, &arm.body);
}

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@ -1,6 +1,5 @@
#![feature(associated_type_defaults)] //needed for Visitor trait
#![feature(trace_macros)]
#![feature(custom_attribute)]
//#![feature(unrestricted_attribute_tokens)]
#![feature(slice_patterns, box_patterns, box_syntax)]
//! `schala-lang` is where the Schala programming language is actually implemented.