From d3d71bb044e0ae9af75bd74d4030e1d95f18a68e Mon Sep 17 00:00:00 2001
From: Martin Kagamino Lehoux <martin@lehoux.net>
Date: Fri, 14 Feb 2025 08:08:57 +0100
Subject: feat(json): Nested parsing

---
 json.c | 67 +++++++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 40 insertions(+), 27 deletions(-)

(limited to 'json.c')

diff --git a/json.c b/json.c
index cf40634..197dca3 100644
--- a/json.c
+++ b/json.c
@@ -9,7 +9,13 @@
 #include "string.h"
 
 typedef struct {
-  int value;
+  JSON *value;
+  uintptr_t pos;
+} parse_any_result;
+parse_any_result parse_any(Arena *a, char *src, uintptr_t pos);
+
+typedef struct {
+  int *value;
   uintptr_t pos;
 } parse_integer_result;
 
@@ -21,11 +27,11 @@ parse_integer_result parse_integer(Arena *a, char *src, uintptr_t pos) {
     ints[i] = val;
     i++;
   }
-  int result = 0;
+  int *result = new (a, int, 1);
   for (int j = 0; j < i; j++) {
-    result += ints[j] * pow(10, (i - j - 1));
+    *result += ints[j] * pow(10, (i - j - 1));
   }
-  printf("json.parse_integer: parsed int=%d at pos=%lu\n", result, pos);
+  printf("json.parse_integer: parsed int=%d at pos=%lu\n", *result, pos);
   return (parse_integer_result){result, pos + i};
 }
 
@@ -42,16 +48,15 @@ typedef struct {
   uintptr_t pos;
 } parse_array_result;
 
-parse_array_result parse_array(Arena *a, char *src, uintptr_t start_pos) {
-  printf("json.parse_array: parsing array %s\n", src + start_pos);
-  assert(src[start_pos] == '[');
-  uintptr_t pos = start_pos + 1;
-  Vec *items = Vec_new(a, JSON, 0);
+parse_array_result parse_array(Arena *a, char *src, uintptr_t pos) {
+  printf("json.parse_array: parsing array %s\n", src + pos);
+  assert(src[pos] == '[');
+  pos++;
+  Vec items = Vec_new(a, JSON, 2);
   for (;;) {
     pos = absorb_whitespaces(src, pos);
-    parse_integer_result result = parse_integer(a, src, pos);
-    assert(result.pos > pos);
-    items = Vec_push(a, items, &result.value);
+    parse_any_result result = parse_any(a, src, pos);
+    Vec_push(a, &items, result.value);
     pos = result.pos;
     pos = absorb_whitespaces(src, pos);
     if (src[pos] == ',') {
@@ -62,7 +67,7 @@ parse_array_result parse_array(Arena *a, char *src, uintptr_t start_pos) {
   };
   assert(src[pos] == ']');
 
-  return (parse_array_result){items, pos + 1};
+  return (parse_array_result){&items, pos + 1};
 }
 
 typedef struct {
@@ -78,31 +83,39 @@ parse_string_result parse_string(Arena *a, char *src, uintptr_t pos) {
   while (src[pos + i] != '"' && src[pos + i - 1] != '\\') {
     i++;
   }
-  assert(src[pos + i]);
+  assert(src[pos + i] == '"');
   Str s = Str_copy(a, &src[pos + 1], i - 1);
 
-  return (parse_string_result){s, pos + i};
+  return (parse_string_result){s, pos + i + 1};
 }
 
-JSON JSON_parse(Arena *a, char *src) {
-  JSON json = {0};
-  int pos = 0;
-  printf("json.parse: src=%s\n", src);
+parse_any_result parse_any(Arena *a, char *src, uintptr_t pos) {
+  JSON *value = new (a, JSON, 1);
   if (isdigit(src[pos])) {
-    parse_integer_result result = parse_integer(a, src, 0);
-    json.integer = &result.value;
+    parse_integer_result result = parse_integer(a, src, pos);
+    value->integer = result.value;
     pos = result.pos;
-  }
-  if (src[pos] == '[') {
+  } else if (src[pos] == '[') {
     parse_array_result result = parse_array(a, src, pos);
-    json.array = result.items;
+    value->array = result.items;
     pos = result.pos;
-  }
-  if (src[pos] == '"') {
+  } else if (src[pos] == '"') {
     parse_string_result result = parse_string(a, src, pos);
-    json.string = &result.string;
+    value->string = &result.string;
     pos = result.pos;
   }
 
+  return (parse_any_result){value, pos};
+}
+
+JSON JSON_parse(Arena *a, char *src) {
+  parse_any_result result = parse_any(a, src, 0);
+  return *result.value;
+}
+
+JSON JSON_Int(Arena *a, int val) {
+  JSON json = {0};
+  json.integer = new (a, int, 1);
+  *json.integer = val;
   return json;
 }
-- 
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