feat(expr): support loading expressions from file

docs/Melon Developer Guide.txt

@@ -3249,6 +3249,9 @@ Their definitions can be found in melon/include/mln_types.h.
       d) mln_expr_val_t *mln_expr_run(mln_string_t *exp, mln_expr_cb_t cb, void *data);
          Run a simple expression `exp`. `cb` will be called with user-data `data` when parsing variables and functions.
 
+      e) mln_expr_val_t *mln_expr_run_file(mln_string_t *path, mln_expr_cb_t cb, void *data);
+         Run the expression in the file indicated by `path`. `cb` will be called with user-data `data` when parsing variables and functions.
+
 5. Framework Usage
    It is very easy to use this framework. Before we use it, we have to initialize it.
    1) include header file.

docs/book/cn/expr.md

@@ -125,6 +125,40 @@ typedef mln_expr_val_t *(*mln_expr_cb_t)(mln_string_t *name, int is_func, mln_ar
 
 
 
+#### mln_expr_run
+
+```c
+mln_expr_val_t *mln_expr_run(mln_string_t *exp, mln_expr_cb_t cb, void *data);
+
+typedef mln_expr_val_t *(*mln_expr_cb_t)(mln_string_t *name, int is_func, mln_array_t *args, void *data);
+```
+
+描述：运行表达式`exp`。表达式中的变量以及函数（和函数的参数）还有用户自定义数据`data`，都会被传递到回调函数`cb`中进行解析。开发者可以根据需求，定制化这些函数和变量的值。
+
+返回值：
+
+- 成功：`mln_expr_val_t`指针，存放运行结果。
+- 失败：`NULL`
+
+
+
+#### mln_expr_run_filr
+
+```c
+mln_expr_val_t *mln_expr_run_file(mln_string_t *path, mln_expr_cb_t cb, void *data);
+
+typedef mln_expr_val_t *(*mln_expr_cb_t)(mln_string_t *name, int is_func, mln_array_t *args, void *data);
+```
+
+描述：运行由`path`指定的文件中的表达式。表达式中的变量以及函数（和函数的参数）还有用户自定义数据`data`，都会被传递到回调函数`cb`中进行解析。开发者可以根据需求，定制化这些函数和变量的值。
+
+返回值：
+
+- 成功：`mln_expr_val_t`指针，存放运行结果。
+- 失败：`NULL`
+
+
+
 ### 示例
 
 ```c

docs/book/en/expr.md

@@ -125,6 +125,23 @@ Return values:
 
 
 
+#### mln_expr_run_file
+
+```c
+mln_expr_val_t *mln_expr_run_file(mln_string_t *path, mln_expr_cb_t cb, void *data);
+
+typedef mln_expr_val_t *(*mln_expr_cb_t)(mln_string_t *name, int is_func, mln_array_t *args, void *data);
+```
+
+Description: Run the expression specified in the file identified by `path`. Variables and functions (along with their arguments) in the expression, as well as user-defined data `data`, will be passed to the callback function `cb` for evaluation. Developers can customize the values of these functions and variables as needed.
+
+Return values:
+
+- On success: Pointer to `mln_expr_val_t`, containing the result of the evaluation
+- On failure: `NULL`
+
+
+
 ### Example
 
 ```c

include/mln_expr.h

@@ -44,6 +44,7 @@ typedef mln_expr_val_t *(*mln_expr_cb_t)(mln_string_t *name, \
                                          void *data);
 
 extern mln_expr_val_t *mln_expr_run(mln_string_t *exp, mln_expr_cb_t cb, void *data);
+extern mln_expr_val_t *mln_expr_run_file(mln_string_t *path, mln_expr_cb_t cb, void *data);
 extern mln_expr_val_t *mln_expr_val_new(mln_expr_typ_t type, void *data, mln_expr_udata_free free);
 extern void mln_expr_val_free(mln_expr_val_t *ev);
 extern void mln_expr_val_dup(mln_expr_val_t *dest, mln_expr_val_t *src);

src/mln_expr.c

@@ -393,6 +393,66 @@ MLN_FUNC(, mln_expr_val_t *, mln_expr_run, (mln_string_t *exp, mln_expr_cb_t cb,
 
         if (eof) {
             mln_expr_val_destroy(&v);
+            if (ret == NULL) ret = mln_expr_val_new(mln_expr_type_null, NULL, NULL);
+            break;
+        }
+
+        if (ret != NULL) mln_expr_val_free(ret);
+        if ((ret = (mln_expr_val_t *)malloc(sizeof(mln_expr_val_t))) != NULL) {
+            mln_expr_val_dup(ret, &v);
+        }
+        mln_expr_val_destroy(&v);
+    }
+
+    if (next != NULL) mln_expr_free(next);
+    mln_lex_destroy(lex);
+    mln_alloc_destroy(pool);
+
+    return ret;
+})
+
+MLN_FUNC(, mln_expr_val_t *, mln_expr_run_file, (mln_string_t *path, mln_expr_cb_t cb, void *data), (path, cb, data), {
+    mln_lex_t *lex = NULL;
+    struct mln_lex_attr lattr;
+    mln_lex_hooks_t hooks;
+    mln_alloc_t *pool;
+    mln_expr_val_t *ret = NULL, v;
+    int eof = 0;
+    mln_expr_struct_t *next = NULL;
+
+    memset(&hooks, 0, sizeof(hooks));
+    hooks.dblq_handler = (lex_hook)mln_expr_dblq_handler;
+    hooks.sglq_handler = (lex_hook)mln_expr_sglq_handler;
+
+    if ((pool = lattr.pool = mln_alloc_init(NULL)) == NULL) {
+        return NULL;
+    }
+    lattr.keywords = keywords;
+    lattr.hooks = &hooks;
+    lattr.preprocess = 1;
+    lattr.padding = 0;
+    lattr.type = M_INPUT_T_FILE;
+    lattr.data = path;
+    lattr.env = NULL;
+
+    mln_lex_init_with_hooks(mln_expr, lex, &lattr);
+    if (lex == NULL) {
+        mln_alloc_destroy(pool);
+        return NULL;
+    }
+
+    while (1) {
+        v.type = mln_expr_type_null;
+        if (mln_expr_parse(lex, cb, data, &v, &eof, &next) != MLN_EXPR_RET_OK) {
+            if (ret != NULL) mln_expr_val_free(ret);
+            ret = NULL;
+            mln_expr_val_destroy(&v);
+            break;
+        }
+
+        if (eof) {
+            mln_expr_val_destroy(&v);
+            if (ret == NULL) ret = mln_expr_val_new(mln_expr_type_null, NULL, NULL);
             break;
         }