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add optional continue expression to while loop

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closes #139
This commit is contained in:
Andrew Kelley 2016-04-19 20:28:44 -07:00
parent 04364c45ce
commit a25307c0a1
9 changed files with 69 additions and 16 deletions
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2
doc/langref.md
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@ -79,7 +79,7 @@ SwitchProng = (list(SwitchItem, ",") | "else") "=>" option("|" "Symbol" "|") Exp
SwitchItem = Expression | (Expression "..." Expression)
WhileExpression = "while" "(" Expression ")" Expression
WhileExpression = "while" "(" Expression option(";" Expression) ")" Expression
ForExpression = "for" "(" Expression ")" option("|" "Symbol" option("," "Symbol") "|") Expression

1
src/all_types.hpp
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@ -486,6 +486,7 @@ struct AstNodeIfVarExpr {
struct AstNodeWhileExpr {
AstNode *condition;
AstNode *continue_expr;
AstNode *body;
// populated by semantic analyzer

5
src/analyze.cpp
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@ -3507,10 +3507,15 @@ static TypeTableEntry *analyze_while_expr(CodeGen *g, ImportTableEntry *import,
AstNode *condition_node = node->data.while_expr.condition;
AstNode *while_body_node = node->data.while_expr.body;
AstNode **continue_expr_node = &node->data.while_expr.continue_expr;
TypeTableEntry *condition_type = analyze_expression(g, import, context,
g->builtin_types.entry_bool, condition_node);
if (*continue_expr_node) {
analyze_expression(g, import, context, g->builtin_types.entry_void, *continue_expr_node);
}
BlockContext *child_context = new_block_context(node, context);
child_context->parent_loop_node = node;

32
src/codegen.cpp
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@ -2282,12 +2282,16 @@ static LLVMValueRef gen_while_expr(CodeGen *g, AstNode *node) {
assert(node->data.while_expr.condition);
assert(node->data.while_expr.body);
AstNode *continue_expr_node = node->data.while_expr.continue_expr;
bool condition_always_true = node->data.while_expr.condition_always_true;
bool contains_break = node->data.while_expr.contains_break;
if (condition_always_true) {
// generate a forever loop
LLVMBasicBlockRef body_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileBody");
LLVMBasicBlockRef continue_block = continue_expr_node ?
LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileContinue") : body_block;
LLVMBasicBlockRef end_block = nullptr;
if (contains_break) {
end_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileEnd");
@ -2296,16 +2300,25 @@ static LLVMValueRef gen_while_expr(CodeGen *g, AstNode *node) {
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, body_block);
if (continue_expr_node) {
LLVMPositionBuilderAtEnd(g->builder, continue_block);
gen_expr(g, continue_expr_node);
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, body_block);
}
LLVMPositionBuilderAtEnd(g->builder, body_block);
g->break_block_stack.append(end_block);
g->continue_block_stack.append(body_block);
g->continue_block_stack.append(continue_block);
gen_expr(g, node->data.while_expr.body);
g->break_block_stack.pop();
g->continue_block_stack.pop();
if (get_expr_type(node->data.while_expr.body)->id != TypeTableEntryIdUnreachable) {
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, body_block);
LLVMBuildBr(g->builder, continue_block);
}
if (contains_break) {
@ -2316,11 +2329,22 @@ static LLVMValueRef gen_while_expr(CodeGen *g, AstNode *node) {
LLVMBasicBlockRef cond_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileCond");
LLVMBasicBlockRef body_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileBody");
LLVMBasicBlockRef continue_block = continue_expr_node ?
LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileContinue") : cond_block;
LLVMBasicBlockRef end_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "WhileEnd");
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, cond_block);
if (continue_expr_node) {
LLVMPositionBuilderAtEnd(g->builder, continue_block);
gen_expr(g, continue_expr_node);
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, cond_block);
}
LLVMPositionBuilderAtEnd(g->builder, cond_block);
LLVMValueRef cond_val = gen_expr(g, node->data.while_expr.condition);
add_debug_source_node(g, node->data.while_expr.condition);
@ -2328,13 +2352,13 @@ static LLVMValueRef gen_while_expr(CodeGen *g, AstNode *node) {
LLVMPositionBuilderAtEnd(g->builder, body_block);
g->break_block_stack.append(end_block);
g->continue_block_stack.append(cond_block);
g->continue_block_stack.append(continue_block);
gen_expr(g, node->data.while_expr.body);
g->break_block_stack.pop();
g->continue_block_stack.pop();
if (get_expr_type(node->data.while_expr.body)->id != TypeTableEntryIdUnreachable) {
add_debug_source_node(g, node);
LLVMBuildBr(g->builder, cond_block);
LLVMBuildBr(g->builder, continue_block);
}
LLVMPositionBuilderAtEnd(g->builder, end_block);

6
src/eval.cpp
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@ -1014,6 +1014,7 @@ static bool eval_while_expr(EvalFn *ef, AstNode *node, ConstExprValue *out_val)
AstNode *cond_node = node->data.while_expr.condition;
AstNode *body_node = node->data.while_expr.body;
AstNode *continue_expr_node = node->data.while_expr.continue_expr;
EvalScope *my_scope = allocate<EvalScope>(1);
my_scope->block_context = body_node->block_context;
@ -1030,6 +1031,11 @@ static bool eval_while_expr(EvalFn *ef, AstNode *node, ConstExprValue *out_val)
ConstExprValue body_val = {0};
if (eval_expr(ef, body_node, &body_val)) return true;
if (continue_expr_node) {
ConstExprValue continue_expr_val = {0};
if (eval_expr(ef, continue_expr_node, &continue_expr_val)) return true;
}
ef->root->branches_used += 1;
}

17
src/parser.cpp
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@ -1886,7 +1886,7 @@ static AstNode *ast_parse_bool_or_expr(ParseContext *pc, int *token_index, bool
}
/*
WhileExpression : token(While) token(LParen) Expression token(RParen) Expression
WhileExpression = "while" "(" Expression option(";" Expression) ")" Expression
*/
static AstNode *ast_parse_while_expr(ParseContext *pc, int *token_index, bool mandatory) {
Token *token = &pc->tokens->at(*token_index);
@ -1904,9 +1904,20 @@ static AstNode *ast_parse_while_expr(ParseContext *pc, int *token_index, bool ma
ast_eat_token(pc, token_index, TokenIdLParen);
node->data.while_expr.condition = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
node->data.while_expr.body = ast_parse_expression(pc, token_index, true);
Token *semi_or_rparen = &pc->tokens->at(*token_index);
if (semi_or_rparen->id == TokenIdRParen) {
*token_index += 1;
node->data.while_expr.body = ast_parse_expression(pc, token_index, true);
} else if (semi_or_rparen->id == TokenIdSemicolon) {
*token_index += 1;
node->data.while_expr.continue_expr = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
node->data.while_expr.body = ast_parse_expression(pc, token_index, true);
} else {
ast_invalid_token_error(pc, semi_or_rparen);
}
normalize_parent_ptrs(node);

7
std/rand.zig
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@ -107,12 +107,9 @@ pub struct Rand {
fn test_float32() {
var r = Rand.init(42);
// TODO for loop with range
var i: i32 = 0;
while (i < 1000) {
{var i: i32 = 0; while (i < 1000; i += 1) {
const val = r.float32();
if (!(val >= 0.0)) unreachable{};
if (!(val < 1.0)) unreachable{};
i += 1;
}
}}
}

4
std/str.zig
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@ -2,9 +2,7 @@ const assert = @import("index.zig").assert;
pub fn len(ptr: &const u8) -> isize {
var count: isize = 0;
while (ptr[count] != 0) {
count += 1;
}
while (ptr[count] != 0; count += 1) {}
return count;
}

11
test/self_hosted.zig
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@ -1258,3 +1258,14 @@ fn pub_enum_test(foo: other.APubEnum) {
fn cast_with_imported_symbol() {
assert(other.size_t(42) == 42);
}
#attribute("test")
fn while_with_continue_expr() {
var sum: i32 = 0;
{var i: i32 = 0; while (i < 10; i += 1) {
if (i == 5) continue;
sum += i;
}}
assert(sum == 40);
}