Implement ability to define global script variables

distr/flecs.h

@@ -14311,7 +14311,10 @@ FLECS_API
 extern ECS_COMPONENT_DECLARE(EcsScript);
 
 FLECS_API
-extern ECS_DECLARE(EcsTemplate);
+extern ECS_DECLARE(EcsScriptTemplate);
+
+FLECS_API
+extern ECS_COMPONENT_DECLARE(EcsScriptConstVar);
 
 FLECS_API
 extern ECS_COMPONENT_DECLARE(EcsScriptFunction);
@@ -14380,6 +14383,14 @@ typedef struct ecs_script_parameter_t {
     ecs_entity_t type;
 } ecs_script_parameter_t;
 
+/** Const component.
+ * This component describes a const variable that can be used from scripts.
+ */
+typedef struct EcsScriptConstVar {
+    ecs_value_t value;
+    const ecs_type_info_t *type_info;
+} EcsScriptConstVar;
+
 /** Function component.
  * This component describes a function that can be called from a script.
  */
@@ -14846,6 +14857,38 @@ char* ecs_script_string_interpolate(
     const ecs_script_vars_t *vars);
 
 
+/* Global const variables */
+
+/** Used with ecs_const_var_init */
+typedef struct ecs_const_var_desc_t {
+    /* Variable name. */
+    const char *name;
+
+    /* Variable parent (namespace). */
+    ecs_entity_t parent;
+
+    /* Variable type. */
+    ecs_entity_t type;
+
+    /* Pointer to value of variable. The value will be copied to an internal
+     * storage and does not need to be kept alive. */
+    void *value;
+} ecs_const_var_desc_t;
+
+/** Create a const variable that can be accessed by scripts. 
+ * 
+ * @param world The world.
+ * @param desc Const var parameters.
+ * @return The const var, or 0 if failed.
+ */
+FLECS_API
+ecs_entity_t ecs_const_var_init(
+    ecs_world_t *world,
+    ecs_const_var_desc_t *desc);
+
+#define ecs_const_var(world, ...)\
+    ecs_const_var_init(world, &(ecs_const_var_desc_t)__VA_ARGS__)
+
 /* Functions */
 
 /** Used with ecs_function_init and ecs_method_init */

include/flecs/addons/script.h

@@ -37,7 +37,10 @@ FLECS_API
 extern ECS_COMPONENT_DECLARE(EcsScript);
 
 FLECS_API
-extern ECS_DECLARE(EcsTemplate);
+extern ECS_DECLARE(EcsScriptTemplate);
+
+FLECS_API
+extern ECS_COMPONENT_DECLARE(EcsScriptConstVar);
 
 FLECS_API
 extern ECS_COMPONENT_DECLARE(EcsScriptFunction);
@@ -106,6 +109,14 @@ typedef struct ecs_script_parameter_t {
     ecs_entity_t type;
 } ecs_script_parameter_t;
 
+/** Const component.
+ * This component describes a const variable that can be used from scripts.
+ */
+typedef struct EcsScriptConstVar {
+    ecs_value_t value;
+    const ecs_type_info_t *type_info;
+} EcsScriptConstVar;
+
 /** Function component.
  * This component describes a function that can be called from a script.
  */
@@ -572,6 +583,38 @@ char* ecs_script_string_interpolate(
     const ecs_script_vars_t *vars);
 
 
+/* Global const variables */
+
+/** Used with ecs_const_var_init */
+typedef struct ecs_const_var_desc_t {
+    /* Variable name. */
+    const char *name;
+
+    /* Variable parent (namespace). */
+    ecs_entity_t parent;
+
+    /* Variable type. */
+    ecs_entity_t type;
+
+    /* Pointer to value of variable. The value will be copied to an internal
+     * storage and does not need to be kept alive. */
+    void *value;
+} ecs_const_var_desc_t;
+
+/** Create a const variable that can be accessed by scripts. 
+ * 
+ * @param world The world.
+ * @param desc Const var parameters.
+ * @return The const var, or 0 if failed.
+ */
+FLECS_API
+ecs_entity_t ecs_const_var_init(
+    ecs_world_t *world,
+    ecs_const_var_desc_t *desc);
+
+#define ecs_const_var(world, ...)\
+    ecs_const_var_init(world, &(ecs_const_var_desc_t)__VA_ARGS__)
+
 /* Functions */
 
 /** Used with ecs_function_init and ecs_method_init */

src/addons/script/expr/ast.h

@@ -16,6 +16,7 @@ typedef enum ecs_expr_node_kind_t {
     EcsExprBinary,
     EcsExprIdentifier,
     EcsExprVariable,
+    EcsExprGlobalVariable,
     EcsExprFunction,
     EcsExprMethod,
     EcsExprMember,
@@ -60,6 +61,7 @@ typedef struct ecs_expr_identifier_t {
 typedef struct ecs_expr_variable_t {
     ecs_expr_node_t node;
     const char *name;
+    ecs_value_t global_value; /* Only set for global variables */
 } ecs_expr_variable_t;
 
 typedef struct ecs_expr_unary_t {

src/addons/script/expr/parser.c

@@ -371,7 +371,18 @@ const char* flecs_script_parse_lhs(
             } else if (!ecs_os_strcmp(expr, "false")) {
                 *out = (ecs_expr_node_t*)flecs_expr_bool(parser, false);
             } else {
-                *out = (ecs_expr_node_t*)flecs_expr_identifier(parser, expr);
+                char *last_elem = strrchr(expr, '.');
+                if (last_elem && last_elem[1] == '$') {
+                    /* Scoped global variable */
+                    ecs_expr_variable_t *v = flecs_expr_variable(parser, expr);
+                    memmove(&last_elem[1], &last_elem[2], 
+                        ecs_os_strlen(&last_elem[2]) + 1);
+                    v->node.kind = EcsExprGlobalVariable;
+                    *out = (ecs_expr_node_t*)v;
+                } else {
+                    /* Entity identifier */
+                    *out = (ecs_expr_node_t*)flecs_expr_identifier(parser, expr);
+                }
             }
             break;
         }

src/addons/script/expr/visit.h

@@ -32,4 +32,8 @@ void flecs_expr_visit_free(
     ecs_script_t *script,
     ecs_expr_node_t *node);
 
+ecs_script_var_t flecs_expr_find_var(
+    ecs_script_t *script,
+    const char *name);
+
 #endif

src/addons/script/expr/visit_eval.c

@@ -275,6 +275,23 @@ int flecs_expr_variable_visit_eval(
     return -1;
 }
 
+static
+int flecs_expr_global_variable_visit_eval(
+    ecs_script_eval_ctx_t *ctx,
+    ecs_expr_variable_t *node,
+    ecs_expr_value_t *out)
+{
+    ecs_assert(ctx->desc != NULL, ECS_INVALID_OPERATION,
+        "variables available at parse time are not provided");
+
+    ecs_assert(node->global_value.type == node->node.type, 
+        ECS_INTERNAL_ERROR, NULL);
+    out->value = node->global_value;
+    out->owned = false;
+
+    return 0;
+}
+
 static
 int flecs_expr_cast_visit_eval(
     ecs_script_eval_ctx_t *ctx,
@@ -558,6 +575,13 @@ int flecs_expr_visit_eval_priv(
             goto error;
         }
         break;
+    case EcsExprGlobalVariable:
+        if (flecs_expr_global_variable_visit_eval(
+            ctx, (ecs_expr_variable_t*)node, out)) 
+        {
+            goto error;
+        }
+        break;
     case EcsExprFunction:
         if (flecs_expr_function_visit_eval(
             ctx, (ecs_expr_function_t*)node, out)) 

src/addons/script/expr/visit_fold.c

@@ -328,6 +328,29 @@ int flecs_expr_variable_visit_fold(
     return 0;
 }
 
+static
+int flecs_expr_global_variable_visit_fold(
+    ecs_script_t *script,
+    ecs_expr_node_t **node_ptr,
+    const ecs_expr_eval_desc_t *desc)
+{
+    (void)desc;
+
+    ecs_expr_variable_t *node = (ecs_expr_variable_t*)*node_ptr;
+    ecs_entity_t type = node->node.type;
+
+    /* Global const variables are always const, so we can always fold */
+
+    ecs_expr_value_node_t *result = flecs_expr_value_from(
+        script, (ecs_expr_node_t*)node, type);
+    void *value = ecs_value_new(script->world, type);
+    ecs_value_copy(script->world, type, value, node->global_value.ptr);
+    result->ptr = value;
+    flecs_visit_fold_replace(script, node_ptr, (ecs_expr_node_t*)result);
+
+    return 0;
+}
+
 static
 int flecs_expr_arguments_visit_fold(
     ecs_script_t *script,
@@ -447,6 +470,11 @@ int flecs_expr_visit_fold(
             goto error;
         }
         break;
+    case EcsExprGlobalVariable:
+        if (flecs_expr_global_variable_visit_fold(script, node_ptr, desc)) {
+            goto error;
+        }
+        break;
     case EcsExprFunction:
     case EcsExprMethod:
         if (flecs_expr_function_visit_fold(script, node_ptr, desc)) {

src/addons/script/expr/visit_free.c

@@ -131,6 +131,7 @@ void flecs_expr_visit_free(
         flecs_free_t(a, ecs_expr_identifier_t, node);
         break;
     case EcsExprVariable:
+    case EcsExprGlobalVariable:
         flecs_free_t(a, ecs_expr_variable_t, node);
         break;
     case EcsExprFunction:

src/addons/script/expr/visit_to_str.c

@@ -267,6 +267,7 @@ int flecs_expr_node_to_str(
         }
         break;
     case EcsExprVariable:
+    case EcsExprGlobalVariable:
         if (flecs_expr_variable_to_str(v, 
             (const ecs_expr_variable_t*)node)) 
         {

src/addons/script/expr/visit_type.c

@@ -733,6 +733,39 @@ int flecs_expr_identifier_visit_type(
     return -1;
 }
 
+static
+int flecs_expr_global_variable_resolve(
+    ecs_script_t *script,
+    ecs_expr_variable_t *node,
+    const ecs_expr_eval_desc_t *desc)
+{
+    ecs_world_t *world = script->world;
+    ecs_entity_t global = desc->lookup_action(
+        world, node->name, desc->lookup_ctx);
+    if (!global) {
+        flecs_expr_visit_error(script, node, "unresolved variable '%s'",
+            node->name);
+        goto error;
+    }
+
+    const EcsScriptConstVar *v = ecs_get(world, global, EcsScriptConstVar);
+    if (!v) {
+        char *str = ecs_get_path(world, global);
+        flecs_expr_visit_error(script, node, 
+            "entity '%s' is not a variable", node->name);
+        ecs_os_free(str);
+        goto error;
+    }
+
+    node->node.kind = EcsExprGlobalVariable;
+    node->node.type = v->value.type;
+    node->global_value = v->value;
+
+    return 0;
+error:
+    return -1;
+}
+
 static
 int flecs_expr_variable_visit_type(
     ecs_script_t *script,
@@ -742,15 +775,33 @@ int flecs_expr_variable_visit_type(
 {
     ecs_script_var_t *var = ecs_script_vars_lookup(
         desc->vars, node->name);
-    if (!var) {
-        flecs_expr_visit_error(script, node, "unresolved variable '%s'",
-            node->name);
-        goto error;
+    if (var) {
+        node->node.type = var->value.type;
+    } else {
+        if (flecs_expr_global_variable_resolve(script, node, desc)) {
+            goto error;
+        }
     }
 
-    node->node.type = var->value.type;
+    *cur = ecs_meta_cursor(script->world, node->node.type, NULL);
 
-    *cur = ecs_meta_cursor(script->world, var->value.type, NULL);
+    return 0;
+error:
+    return -1;
+}
+
+static
+int flecs_expr_global_variable_visit_type(
+    ecs_script_t *script,
+    ecs_expr_variable_t *node,
+    ecs_meta_cursor_t *cur,
+    const ecs_expr_eval_desc_t *desc)
+{
+    (void)cur;
+
+    if (flecs_expr_global_variable_resolve(script, node, desc)) {
+        goto error;
+    }
 
     return 0;
 error:
@@ -1125,6 +1176,13 @@ int flecs_expr_visit_type_priv(
             goto error;
         }
         break;
+    case EcsExprGlobalVariable:
+        if (flecs_expr_global_variable_visit_type(
+            script, (ecs_expr_variable_t*)node, cur, desc)) 
+        {
+            goto error;
+        }
+        break;
     case EcsExprFunction:
         if (flecs_expr_function_visit_type(
             script, (ecs_expr_function_t*)node, cur, desc))