if-then-else AST node - this one is not for ternary expressions

[xonotic/gmqcc.git] / ast.h

diff --git a/ast.h b/ast.h
index 411a75851c42e89a7eaee4745b705aa9b0f7e095..c9311eeb7e4e6b96eaf23785029a509ec108f4ed 100644 (file)
--- a/ast.h
+++ b/ast.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 
+ * Copyright (C) 2012
  *     Wolfgang Bumiller
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
@@ -36,6 +36,8 @@ typedef struct ast_function_s   ast_function;
 typedef struct ast_block_s      ast_block;
 typedef struct ast_binary_s     ast_binary;
 typedef struct ast_store_s      ast_store;
+typedef struct ast_entfield_s   ast_entfield;
+typedef struct ast_ifthen_s     ast_ifthen;
 
 /* Node interface with common components
  */
@@ -66,6 +68,7 @@ typedef struct
  */
 typedef bool ast_expression_codegen(ast_expression*,
                                     ast_function*,
+                                    bool lvalue,
                                     ir_value**);
 typedef struct
 {
@@ -112,7 +115,7 @@ void ast_value_delete(ast_value*);
 
 bool ast_value_set_name(ast_value*, const char *name);
 
-bool ast_value_codegen(ast_value*, ast_function*, ir_value**);
+bool ast_value_codegen(ast_value*, ast_function*, bool lvalue, ir_value**);
 
 /* Binary
  *
@@ -132,10 +135,33 @@ ast_binary* ast_binary_new(lex_ctx    ctx,
                            ast_expression *right);
 void ast_binary_delete(ast_binary*);
 
-/* hmm, seperate functions?
-bool ast_block_codegen(ast_block*, ast_function*, ir_value**);
+bool ast_binary_codegen(ast_binary*, ast_function*, bool lvalue, ir_value**);
+
+/* Entity-field
+ *
+ * This must do 2 things:
+ * -) Provide a way to fetch an entity field value. (Rvalue)
+ * -) Provide a pointer to an entity field. (Lvalue)
+ * The problem:
+ * In original QC, there's only a STORE via pointer, but
+ * no LOAD via pointer.
+ * So we must know beforehand if we are going to read or assign
+ * the field.
+ * For this we will have to extend the codegen() functions with
+ * a flag saying whether or not we need an L or an R-value.
  */
-bool ast_binary_codegen(ast_binary*, ast_function*, ir_value**);
+struct ast_entfield_s
+{
+    ast_expression_common expression;
+    /* The entity can come from an expression of course. */
+    ast_expression *entity;
+    /* As can the field, it just must result in a value of TYPE_FIELD */
+    ast_expression *field;
+};
+ast_entfield* ast_entfield_new(lex_ctx ctx, ast_expression *entity, ast_expression *field);
+void ast_entfield_delete(ast_entfield*);
+
+bool ast_entfield_codegen(ast_entfield*, ast_function*, bool lvalue, ir_value**);
 
 /* Store
  *
@@ -153,7 +179,31 @@ ast_store* ast_store_new(lex_ctx ctx, int op,
                          ast_value *d, ast_expression *s);
 void ast_store_delete(ast_store*);
 
-bool ast_store_codegen(ast_store*, ast_function*, ir_value**);
+bool ast_store_codegen(ast_store*, ast_function*, bool lvalue, ir_value**);
+
+/* If
+ *
+ * A general 'if then else' statement, either side can be NULL and will
+ * thus be omitted. It is an error for *both* cases to be NULL at once.
+ *
+ * During its 'codegen' it'll be changing the ast_function's block.
+ *
+ * An if is also an "expression". Its codegen will put NULL into the
+ * output field though. For ternary expressions an ast_ternary will be
+ * added.
+ */
+struct ast_ifthen_s
+{
+    ast_expression_common expression;
+    ast_expression *cond;
+    /* It's all just 'expressions', since an ast_block is one too. */
+    ast_expression *on_true;
+    ast_expression *on_false;
+};
+ast_ifthen* ast_ifthen_new(lex_ctx ctx, ast_expression *cond, ast_expression *ontrue, ast_expression *onfalse);
+void ast_ifthen_delete(ast_ifthen*);
+
+bool ast_ifthen_codegen(ast_ifthen*, ast_function*, bool lvalue, ir_value**);
 
 /* Blocks
  *
@@ -171,7 +221,7 @@ void ast_block_delete(ast_block*);
 MEM_VECTOR_PROTO(ast_block, ast_value*, locals);
 MEM_VECTOR_PROTO(ast_block, ast_expression*, exprs);
 
-bool ast_block_codegen(ast_block*, ast_function*, ir_value**);
+bool ast_block_codegen(ast_block*, ast_function*, bool lvalue, ir_value**);
 
 /* Function
  *