feat: hel: render without execute

package/c/hel/Makefile

@@ -0,0 +1,13 @@
+MODULE_big = hel
+OBJS = hel.o
+EXTENSION = hel
+DATA = hel--0.1.sql
+
+PG_CONFIG = pg_config
+
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+
+# Add hectic library path
+CFLAGS += -I -lhectic
+
+include $(PGXS)

package/c/hel/hel--0.1.sql

@@ -0,0 +1,26 @@
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION hel" to load this file. \quit
+
+CREATE SCHEMA hel;
+
+-- Define the parse_text_with_hectic function that uses hectic library
+-- Expected usage:
+--   ```sql
+--    SELECT "hel"."render"(
+--      "declare" := 
+--        jsonb_build_object(
+--          'name', 'test',
+--          'config', jsonb_build_object(
+--            'debug', true,
+--            'limit', 100
+--          )
+--        ),
+--      "template" := $hel$
+--        {{ name }} {{ config.limit }}
+--      $hel$
+--    ); 
+--   ```
+CREATE FUNCTION "hel"."render"("declare" json, "template" text)
+RETURNS text
+AS 'hel', 'render'
+LANGUAGE C STRICT;

package/c/hel/hel.c

@@ -0,0 +1,307 @@
+#include "postgres.h"
+#include "fmgr.h"
+#include "utils/builtins.h"
+#include "utils/json.h"
+#include "hectic.h"
+#include <string.h>
+
+#ifdef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+
+/* Helper function to get a JSON value by key path */
+static Json *json_get_by_path(Arena *arena, const Json *context, const char *key_path) {
+    if (!context || !key_path || !*key_path) {
+        return NULL;
+    }
+    
+    char *path_copy = arena_strdup(arena, key_path);
+    char *token = strtok(path_copy, ".");
+    Json *current = (Json*)context;
+    
+    while (token && current) {
+        current = json_get_object_item(current, token);
+        token = strtok(NULL, ".");
+    }
+    
+    return current;
+}
+
+/* Convert JSON value to string */
+static char *json_value_to_string(Arena *arena, const Json *json) {
+    if (!json) {
+        return "";
+    }
+    
+    switch (json->type) {
+        case JSON_STRING:
+            return json->value.string;
+        case JSON_NUMBER: {
+            char *buf = arena_alloc(arena, 64);
+            snprintf(buf, 64, "%.6g", json->value.number);
+            return buf;
+        }
+        case JSON_BOOL:
+            return json->value.boolean ? "true" : "false";
+        case JSON_NULL:
+            return "";
+        case JSON_ARRAY:
+        case JSON_OBJECT:
+            return json_to_string(arena, json);
+        default:
+            return "";
+    }
+}
+
+/* Forward declaration for recursive function */
+static char *render_template_node(Arena *arena, const TemplateNode *node, const Json *context);
+
+/* Render a text node */
+static char *render_text_node(Arena *arena, const TemplateNode *node) {
+    if (!node || node->type != TEMPLATE_NODE_TEXT) {
+        return "";
+    }
+    
+    return node->value.text.content;
+}
+
+/* Render an interpolation node */
+static char *render_interpolation_node(Arena *arena, const TemplateNode *node, const Json *context) {
+    if (!node || node->type != TEMPLATE_NODE_INTERPOLATE || !context) {
+        return "";
+    }
+    
+    const char *key = node->value.interpolate.key;
+    Json *value = json_get_by_path(arena, context, key);
+    
+    if (!value) {
+        return "";
+    }
+    
+    return json_value_to_string(arena, value);
+}
+
+/* Render a section node (for loop) */
+static char *render_section_node(Arena *arena, const TemplateNode *node, const Json *context) {
+    if (!node || node->type != TEMPLATE_NODE_SECTION || !context) {
+        return "";
+    }
+    
+    const char *collection_key = node->value.section.collection;
+    const char *iterator_name = node->value.section.iterator;
+    TemplateNode *body = node->value.section.body;
+    
+    Json *collection = json_get_by_path(arena, context, collection_key);
+    
+    if (!collection || collection->type != JSON_ARRAY) {
+        return "";
+    }
+    
+    size_t buffer_size = 1024;
+    char *buffer = arena_alloc(arena, buffer_size);
+    size_t buffer_pos = 0;
+    
+    Json *item = collection->value.child;
+    while (item) {
+        const char *empty_json = "{}";
+        Json *iter_context = json_parse(arena, &empty_json);
+        if (!iter_context) {
+            return "";
+        }
+        
+        Json *item_json = arena_alloc(arena, sizeof(Json));
+        memcpy(item_json, item, sizeof(Json));
+        item_json->key = arena_strdup(arena, iterator_name);
+        item_json->next = NULL;
+        
+        char *rendered_body = render_template_node(arena, body, iter_context);
+        
+        size_t rendered_len = strlen(rendered_body);
+        if (buffer_pos + rendered_len + 1 > buffer_size) {
+            buffer_size = (buffer_pos + rendered_len + 1) * 2;
+            buffer = arena_realloc(arena, buffer, buffer_size / 2, buffer_size);
+        }
+        
+        strcpy(buffer + buffer_pos, rendered_body);
+        buffer_pos += rendered_len;
+        
+        item = item->next;
+    }
+    
+    buffer[buffer_pos] = '\0';
+    return buffer;
+}
+
+/* Render an include node */
+static char *render_include_node(Arena *arena, const TemplateNode *node, const Json *context) {
+    if (!node || node->type != TEMPLATE_NODE_INCLUDE || !context) {
+        return "";
+    }
+    
+    const char *include_key = node->value.include.key;
+    Json *include_value = json_get_by_path(arena, context, include_key);
+    
+    if (!include_value || include_value->type != JSON_ARRAY) {
+        return "";
+    }
+    
+    char *buffer = arena_alloc(arena, 1024);
+    size_t buffer_pos = 0;
+    
+    Json *include_item = include_value->value.child;
+    while (include_item) {
+        if (include_item->type == JSON_OBJECT) {
+            Json *template_json = json_get_object_item(include_item, "template");
+            Json *content_json = json_get_object_item(include_item, "content");
+            Json *context_json = json_get_object_item(include_item, "context");
+            
+            if (template_json && template_json->type == JSON_STRING) {
+                const char *template_str = template_json->value.string;
+                const Json *include_context = context_json ? context_json : context;
+                
+                TemplateConfig config = template_default_config();
+                TemplateResult template_result = template_parse(arena, &template_str, &config);
+                
+                if (!IS_RESULT_ERROR(template_result)) {
+                    TemplateNode template_node = RESULT_SOME_VALUE(template_result);
+                    
+                    char *rendered = render_template_node(arena, &template_node, include_context);
+                    
+                    buffer_pos += sprintf(buffer + buffer_pos, "%s", rendered);
+                }
+            } else if (content_json && content_json->type == JSON_STRING) {
+                buffer_pos += sprintf(buffer + buffer_pos, "%s", content_json->value.string);
+            }
+        }
+        
+        include_item = include_item->next;
+    }
+    
+    buffer[buffer_pos] = '\0';
+    return buffer;
+}
+
+/* Render a template node tree recursively */
+static char *render_template_node(Arena *arena, const TemplateNode *node, const Json *context) {
+    if (!node) {
+        return "";
+    }
+    
+    size_t buffer_size = 4096;
+    char *output = arena_alloc(arena, buffer_size);
+    size_t output_pos = 0;
+    
+    const TemplateNode *current = node;
+    while (current) {
+        char *rendered = NULL;
+        
+        switch (current->type) {
+            case TEMPLATE_NODE_TEXT:
+                rendered = render_text_node(arena, current);
+                break;
+                
+            case TEMPLATE_NODE_INTERPOLATE:
+                rendered = render_interpolation_node(arena, current, context);
+                break;
+                
+            case TEMPLATE_NODE_SECTION:
+                rendered = render_section_node(arena, current, context);
+                break;
+                
+            case TEMPLATE_NODE_INCLUDE:
+                rendered = render_include_node(arena, current, context);
+                break;
+                
+            case TEMPLATE_NODE_EXECUTE:
+                todo;
+                rendered = "";
+                break;
+                
+            default:
+                rendered = "";
+                break;
+        }
+        
+        size_t rendered_len = strlen(rendered);
+        if (output_pos + rendered_len + 1 > buffer_size) {
+            buffer_size = (output_pos + rendered_len + 1) * 2;
+            output = arena_realloc(arena, output, buffer_size / 2, buffer_size);
+        }
+        
+        strcpy(output + output_pos, rendered);
+        output_pos += rendered_len;
+        
+        if (current->children) {
+            char *children_rendered = render_template_node(arena, current->children, context);
+            size_t children_len = strlen(children_rendered);
+            
+            if (output_pos + children_len + 1 > buffer_size) {
+                buffer_size = (output_pos + children_len + 1) * 2;
+                output = arena_realloc(arena, output, buffer_size / 2, buffer_size);
+            }
+            
+            strcpy(output + output_pos, children_rendered);
+            output_pos += children_len;
+        }
+        
+        current = current->next;
+    }
+    
+    output[output_pos] = '\0';
+    return output;
+}
+
+/* Define the function render */
+PG_FUNCTION_INFO_V1(render);
+
+/* 
+ * Function to render templates using hectic library with JSON context
+ * Arguments:
+ *   1. declare - JSON context for rendering
+ *   2. template - The template text to render
+ */
+Datum render(PG_FUNCTION_ARGS)
+{
+    text *context_text = PG_GETARG_TEXT_PP(0);
+    text *template_text = PG_GETARG_TEXT_PP(1);
+    
+    /* Convert input text to C string */
+    char *template_str = text_to_cstring(template_text);
+    char *context_str = text_to_cstring(context_text);
+    
+    /* Initialize arena for memory management */
+    Arena arena = arena_init(MEM_MiB);
+    
+    /* Parse the JSON context */
+    const char *json_ptr = context_str;
+    Json *context = json_parse(&arena, &json_ptr);
+    
+    if (!context) {
+        arena_free(&arena);
+        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                 errmsg("Invalid JSON context")));
+    }
+    
+    /* Parse the template text */
+    const char *template_ptr = template_str;
+    TemplateConfig config = template_default_config();
+    TemplateResult template_result = template_parse(&arena, &template_ptr, &config);
+    
+    if (IS_RESULT_ERROR(template_result)) {
+        arena_free(&arena);
+        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                 errmsg("Failed to parse template: %s", 
+                        RESULT_ERROR_MESSAGE(template_result))));
+    }
+    
+    /* Render the template */
+    TemplateNode root_node = RESULT_SOME_VALUE(template_result);
+    char *result_str = render_template_node(&arena, &root_node, context);
+    
+    /* Prepare return value */
+    text *result = cstring_to_text(result_str);
+    
+    arena_free(&arena);
+    
+    PG_RETURN_TEXT_P(result);
+}

package/c/hel/hel.control

@@ -0,0 +1,3 @@
+comment = 'My first extension'
+default_version = '0.1'
+module_pathname = '$libdir/hel'

package/c/hel/make.sh

@@ -0,0 +1,102 @@
+#!/bin/sh
+# Usage: make.sh [build|watch] [--debug] [--color]
+# Options:
+#   build         Build the postgres extension (default if no mode is provided).
+#   watch         Build the extension and watch for changes.
+#   --debug       Build with -O0 (debug mode).
+#   --color       Pass -fdiagnostics-color=always to compiler.
+#   help, --help  Show this help message.
+
+check_dependencies() {
+  for dep in gcc pg_config; do
+    if ! command -v "$dep" >/dev/null 2>&1; then
+      echo "Error: Required dependency '$dep' not found." >&2
+      exit 1
+    fi
+  done
+  
+  # Check for either fswatch or inotifywait for watch mode
+  if [ "$MODE" = "watch" ] && ! command -v fswatch >/dev/null 2>&1 && ! command -v inotifywait >/dev/null 2>&1; then
+    echo "Error: Neither fswatch nor inotifywait found. Please install one of them." >&2
+    echo "  On macOS: brew install fswatch" >&2
+    echo "  On Linux: sudo apt install inotify-tools" >&2
+    exit 1
+  fi
+}
+
+print_help() {
+  cat <<EOF
+Usage: $0 [build|watch] [--debug] [--color]
+  build         Build the postgres extension (default).
+  watch         Build the extension and watch for changes.
+  --debug       Build with debug flags (-O0).
+  --color       Force colored compiler diagnostics.
+  help, --help  Display this help message.
+EOF
+}
+
+# Show help if requested
+case "$1" in
+  help|--help)
+    print_help
+    exit 0
+    ;;
+esac
+
+# Default flags
+OPTFLAGS="-O2"
+CFLAGS="-Wall -Wextra -pedantic -fPIC"
+COLOR_FLAG=""
+DEBUG=0
+
+# Process options
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --debug)
+      OPTFLAGS="-O0 -gdwarf-2 -g3 -Wno-error"
+      DEBUG=1
+      ;;
+    --color)
+      COLOR_FLAG="-fdiagnostics-color=always"
+      ;;
+    *)
+      break
+      ;;
+  esac
+  shift
+done
+
+MODE="${1:-build}"
+shift 2> /dev/null
+
+if [ -n "$COLOR_FLAG" ]; then
+  CFLAGS="$CFLAGS $COLOR_FLAG"
+fi
+
+check_dependencies
+
+# Get PostgreSQL include directory
+PG_INCLUDE=$(pg_config --includedir-server)
+PG_LIBDIR=$(pg_config --libdir)
+
+case "$MODE" in
+  watch)
+    find . -type d | nix run .#watch -- 'sh ./make.sh build' -p '*.c' -p '*.h' 2>&1
+    ;;
+  build)
+    mkdir -p target
+    echo "# Building PostgreSQL extension"
+    # shellcheck disable=SC2086
+    gcc $CFLAGS $OPTFLAGS -I$PG_INCLUDE -shared -o target/hel.so hel.c
+    
+    # Copy extension files to target directory
+    cp hel.control target/
+    cp hel--0.1.sql target/
+    
+    echo "Build complete. Files available in target/ directory."
+    ;;
+  *)
+    print_help
+    exit 1
+    ;;
+esac