From 872b3103e8aa87cb9911f96fe0c151c1743d0f91 Mon Sep 17 00:00:00 2001
From: Aaron Councilman <aaronjc4@illinois.edu>
Date: Mon, 17 Feb 2025 19:24:42 -0600
Subject: [PATCH] Allow more rust-like for loops
---
juno_frontend/src/lang.l | 1 +
juno_frontend/src/lang.y | 20 +++++++++++++-------
juno_frontend/src/semant.rs | 16 +++++++++++++---
3 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/juno_frontend/src/lang.l b/juno_frontend/src/lang.l
index 4039ef0a..6399e5f2 100644
--- a/juno_frontend/src/lang.l
+++ b/juno_frontend/src/lang.l
@@ -28,6 +28,7 @@ for "for"
if "if"
inout "inout"
integer "integer"
+in "in"
let "let"
match "match"
mod "mod"
diff --git a/juno_frontend/src/lang.y b/juno_frontend/src/lang.y
index 7efc0125..a5b82452 100644
--- a/juno_frontend/src/lang.y
+++ b/juno_frontend/src/lang.y
@@ -292,11 +292,17 @@ Stmt -> Result<Stmt, ()>
| 'match' NonStructExpr Cases
{ Ok(Stmt::MatchStmt{ span : $span, expr : $2?, body : $3? }) }
| 'for' VarBind '=' NonStructExpr 'to' NonStructExpr Stmts
- { Ok(Stmt::ForStmt{ span : $span, var : $2?, init : $4?, bound : $6?, step : None,
- body : Box::new($7?) }) }
+ { Ok(Stmt::ForStmt{ span : $span, var : $2?, init : $4?, bound : $6?,
+ inclusive: false, step : None, body : Box::new($7?) }) }
| 'for' VarBind '=' NonStructExpr 'to' NonStructExpr 'by' SignedIntLit Stmts
- { Ok(Stmt::ForStmt{ span : $span, var : $2?, init : $4?, bound : $6?, step : Some($8?),
- body : Box::new($9?) }) }
+ { Ok(Stmt::ForStmt{ span : $span, var : $2?, init : $4?, bound : $6?,
+ inclusive: false, step : Some($8?), body : Box::new($9?) }) }
+ | 'for' VarBind 'in' NonStructExpr '..' NonStructExpr Stmts
+ { Ok(Stmt::ForStmt{ span: $span, var: $2?, init: $4?, bound: $6?,
+ inclusive: false, step: None, body: Box::new($7?) }) }
+ | 'for' VarBind 'in' NonStructExpr '..' '=' NonStructExpr Stmts
+ { Ok(Stmt::ForStmt{ span: $span, var: $2?, init: $4?, bound: $7?,
+ inclusive: false, step: None, body: Box::new($8?) }) }
| 'while' NonStructExpr Stmts
{ Ok(Stmt::WhileStmt{ span : $span, cond : $2?, body : Box::new($3?) }) }
| 'return' ';'
@@ -687,9 +693,9 @@ pub enum Stmt {
AssignStmt { span : Span, lhs : LExpr, assign : AssignOp, assign_span : Span, rhs : Expr },
IfStmt { span : Span, cond : Expr, thn : Box<Stmt>, els : Option<Box<Stmt>> },
MatchStmt { span : Span, expr : Expr, body : Vec<Case> },
- // The step records: negative, number, base
- ForStmt { span : Span, var : VarBind, init : Expr, bound : Expr, step : Option<(bool, Span, IntBase)>,
- body : Box<Stmt> },
+ // The step records: negative, number, base, inclusive records whether the bound is included in the range
+ ForStmt { span : Span, var : VarBind, init : Expr, bound : Expr,
+ inclusive: bool, step : Option<(bool, Span, IntBase)>, body : Box<Stmt> },
WhileStmt { span : Span, cond : Expr, body : Box<Stmt> },
ReturnStmt { span : Span, expr : Option<Expr> },
BreakStmt { span : Span },
diff --git a/juno_frontend/src/semant.rs b/juno_frontend/src/semant.rs
index 1059229a..bfd4cf7f 100644
--- a/juno_frontend/src/semant.rs
+++ b/juno_frontend/src/semant.rs
@@ -1999,6 +1999,7 @@ fn process_stmt(
},
init,
bound,
+ inclusive,
step,
body,
} => {
@@ -2130,10 +2131,19 @@ fn process_stmt(
val: bound_val,
};
- // The condition of the loop is var < bound, unless the step is negative in which case
- // it is var > bound
+ // There are four cases for the condition that we generate, though it always takes the
+ // form var OP bound:
+ // 1. The step is positive and the range is exclusive of the bound, OP = <
+ // 2. The step is positive and the range is inclusive of the bound, OP = <=
+ // 3. The step is negative and the range is exclusive of the bound, OP = >
+ // 4. The step is negative and the range is inclusive of the bound, OP = >=
let condition = Expr::BinaryExp {
- op: if step_pos { BinaryOp::Lt } else { BinaryOp::Gt },
+ op: match (step_pos, inclusive) {
+ (true, false) => BinaryOp::Lt,
+ (true, true) => BinaryOp::Le,
+ (false, false) => BinaryOp::Gt,
+ (false, true) => BinaryOp::Ge,
+ },
lhs: Box::new(Expr::Variable {
var: var,
typ: var_type,
--
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