hanez/fun
1
0
Fork 0
forked from fun/fun
Code Pull requests Activity

Loops, break and continue.

Browse source
This commit is contained in:
Johannes Findeisen 2025-09-15 03:21:57 +02:00
commit 0b48aa3e0c
2 changed files with 134 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

31
examples/loops_break_continue.fun Executable file
View file

@ -0,0 +1,31 @@
#!/usr/bin/env fun
// break and continue examples
// 1) while loop: print odd numbers, stop after printing 7
number i = 0
while i < 10
if i % 2 == 0
i = i + 1
continue
print(i) // -> 1, 3, 5, 7
if i > 5
break
i = i + 1
// 2) for range: skip 3, stop at 6
for i in range(0, 8)
if i == 3
continue
print(i) // -> 0, 1, 2, 4, 5, 6
if i == 6
break
// 3) for-in over array: skip 3, break at 4
arr = [1, 2, 3, 4, 5]
for x in arr
if x == 3
continue
print(x) // -> 1, 2, 4
if x == 4
break

107
src/parser.c
View file

@ -230,6 +230,17 @@ typedef struct {
static LocalEnv *g_locals = NULL;
/* loop context for break/continue patching */
typedef struct LoopCtx {
int break_jumps[64];
int break_count;
int continue_jumps[64];
int cont_count;
struct LoopCtx *prev;
} LoopCtx;
static LoopCtx *g_loop_ctx = NULL;
static int local_find(const char *name) {
if (!g_locals) return -1;
for (int i = 0; i < g_locals->count; ++i) {
@ -976,6 +987,42 @@ static void parse_simple_statement(Bytecode *bc, const char *src, size_t len, si
return;
}
/* break / continue */
if (strcmp(name, "break") == 0) {
free(name);
if (!g_loop_ctx) {
parser_fail(local_pos, "break used outside of loop");
return;
}
int j = bytecode_add_instruction(bc, OP_JUMP, 0);
if (g_loop_ctx->break_count < (int)(sizeof(g_loop_ctx->break_jumps) / sizeof(g_loop_ctx->break_jumps[0]))) {
g_loop_ctx->break_jumps[g_loop_ctx->break_count++] = j;
} else {
parser_fail(local_pos, "Too many 'break' in one loop");
return;
}
*pos = local_pos;
skip_to_eol(src, len, pos);
return;
}
if (strcmp(name, "continue") == 0) {
free(name);
if (!g_loop_ctx) {
parser_fail(local_pos, "continue used outside of loop");
return;
}
int j = bytecode_add_instruction(bc, OP_JUMP, 0);
if (g_loop_ctx->cont_count < (int)(sizeof(g_loop_ctx->continue_jumps) / sizeof(g_loop_ctx->continue_jumps[0]))) {
g_loop_ctx->continue_jumps[g_loop_ctx->cont_count++] = j;
} else {
parser_fail(local_pos, "Too many 'continue' in one loop");
return;
}
*pos = local_pos;
skip_to_eol(src, len, pos);
return;
}
/* typed declarations: number|string|boolean <ident> (= expr)? */
if (strcmp(name, "number") == 0 || strcmp(name, "string") == 0 || strcmp(name, "boolean") == 0) {
int is_number = (strcmp(name, "number") == 0);
@ -1363,6 +1410,10 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
bytecode_add_instruction(bc, OP_LT, 0);
int jmp_false = bytecode_add_instruction(bc, OP_JUMP_IF_FALSE, 0);
/* enter loop context for break/continue */
LoopCtx ctx = { {0}, 0, {0}, 0, g_loop_ctx };
g_loop_ctx = &ctx;
/* parse body at increased indent (peek) */
int body_indent = 0;
size_t look_body = *pos;
@ -1372,6 +1423,9 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* empty body ok */
}
/* continue target: start of increment */
int cont_label = bc->instr_count;
/* i = i + 1 */
int c1 = bytecode_add_constant(bc, make_int(1));
if (lidx >= 0) {
@ -1388,7 +1442,19 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* back edge and patch */
bytecode_add_instruction(bc, OP_JUMP, loop_start);
bytecode_set_operand(bc, jmp_false, bc->instr_count);
/* end label (after loop) */
int end_label = bc->instr_count;
bytecode_set_operand(bc, jmp_false, end_label);
/* patch continue/break jumps */
for (int bi = 0; bi < ctx.cont_count; ++bi) {
bytecode_set_operand(bc, ctx.continue_jumps[bi], cont_label);
}
for (int bi = 0; bi < ctx.break_count; ++bi) {
bytecode_set_operand(bc, ctx.break_jumps[bi], end_label);
}
g_loop_ctx = ctx.prev;
free(ivar);
continue;
@ -1489,6 +1555,10 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
bytecode_add_instruction(bc, OP_STORE_GLOBAL, gdst);
}
/* enter loop context for break/continue */
LoopCtx ctx = { {0}, 0, {0}, 0, g_loop_ctx };
g_loop_ctx = &ctx;
/* parse body at increased indent */
int body_indent = 0;
size_t look_body = *pos;
@ -1498,6 +1568,9 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* empty body ok */
}
/* continue target: start of increment */
int cont_label = bc->instr_count;
/* i = i + 1 */
int c1 = bytecode_add_constant(bc, make_int(1));
if (li >= 0) {
@ -1514,7 +1587,19 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* back edge and patch */
bytecode_add_instruction(bc, OP_JUMP, loop_start);
bytecode_set_operand(bc, jmp_false, bc->instr_count);
/* end label (after loop) */
int end_label = bc->instr_count;
bytecode_set_operand(bc, jmp_false, end_label);
/* patch continue/break jumps */
for (int bi = 0; bi < ctx.cont_count; ++bi) {
bytecode_set_operand(bc, ctx.continue_jumps[bi], cont_label);
}
for (int bi = 0; bi < ctx.break_count; ++bi) {
bytecode_set_operand(bc, ctx.break_jumps[bi], end_label);
}
g_loop_ctx = ctx.prev;
free(ivar);
continue;
@ -1637,6 +1722,10 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* jump over body if false */
int jmp_false = bytecode_add_instruction(bc, OP_JUMP_IF_FALSE, 0);
/* enter loop context (continue -> condition) */
LoopCtx ctx = { {0}, 0, {0}, 0, g_loop_ctx };
g_loop_ctx = &ctx;
/* parse body at increased indent (peek indent without advancing pos) */
int body_indent = 0;
size_t look_body = *pos;
@ -1646,11 +1735,21 @@ static void parse_block(Bytecode *bc, const char *src, size_t len, size_t *pos,
/* empty body allowed */
}
/* patch pending continues to loop_start (re-evaluate condition) */
for (int bi = 0; bi < ctx.cont_count; ++bi) {
bytecode_set_operand(bc, ctx.continue_jumps[bi], loop_start);
}
/* back edge to loop start */
bytecode_add_instruction(bc, OP_JUMP, loop_start);
/* patch false jump to here (after body) */
bytecode_set_operand(bc, jmp_false, bc->instr_count);
/* end label and patches */
int end_label = bc->instr_count;
bytecode_set_operand(bc, jmp_false, end_label);
for (int bi = 0; bi < ctx.break_count; ++bi) {
bytecode_set_operand(bc, ctx.break_jumps[bi], end_label);
}
g_loop_ctx = ctx.prev;
continue;
}