Добавлена конструкция IF-THEN-ELSE-END

[dsw-obn.git] / src / oberon.c

diff --git a/src/oberon.c b/src/oberon.c
index f2310db26de0ab2b1bffb82efee2a4b346bf7052..5816c2b3fb0a96f2076f0e6ff82fbeb2b87058d2 100644 (file)
--- a/src/oberon.c
+++ b/src/oberon.c
@@ -61,7 +61,10 @@ enum {
        IMPORT,
        REAL,
        CHAR,
-       STRING
+       STRING,
+       IF,
+       THEN,
+       ELSE
 };
 
 // =======================================================================
@@ -380,6 +383,18 @@ oberon_read_ident(oberon_context_t * ctx)
        {
                ctx -> token = IS;
        }
+       else if(strcmp(ident, "IF") == 0)
+       {
+               ctx -> token = IF;
+       }
+       else if(strcmp(ident, "THEN") == 0)
+       {
+               ctx -> token = THEN;
+       }
+       else if(strcmp(ident, "ELSE") == 0)
+       {
+               ctx -> token = ELSE;
+       }
 }
 
 static void
@@ -1641,6 +1656,10 @@ oberon_make_bin_op(oberon_context_t * ctx, int token, oberon_expr_t * a, oberon_
                                || b -> result -> class == OBERON_TYPE_INTEGER
                                || a -> result -> class == OBERON_TYPE_REAL
                                || b -> result -> class == OBERON_TYPE_REAL)
+                       {
+                               // accept
+                       }
+                       else
                        {
                                oberon_error(ctx, "used only with numeric types");
                        }
@@ -2845,6 +2864,9 @@ oberon_decl_seq(oberon_context_t * ctx)
        oberon_prevent_undeclarated_procedures(ctx);
 }
 
+static void
+oberon_statement_seq(oberon_context_t * ctx);
+
 static void
 oberon_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
 {
@@ -2877,6 +2899,36 @@ oberon_statement(oberon_context_t * ctx)
                        oberon_opt_proc_parens(ctx, item1);
                }
        }
+       else if(ctx -> token == IF)
+       {
+               gen_label_t * end;
+               gen_label_t * els;
+               oberon_expr_t * cond;
+
+               els = oberon_generator_reserve_label(ctx);
+               end = oberon_generator_reserve_label(ctx);
+
+               oberon_assert_token(ctx, IF);
+               cond = oberon_expr(ctx);
+               if(cond -> result -> class != OBERON_TYPE_BOOLEAN)
+               {
+                       oberon_error(ctx, "condition must be boolean");
+               }
+               oberon_assert_token(ctx, THEN);
+               oberon_generate_branch(ctx, cond, false, els);
+               oberon_statement_seq(ctx);
+               oberon_generate_goto(ctx, end);
+
+               if(ctx -> token == ELSE)
+               {
+                       oberon_generate_label(ctx, els);
+                       oberon_assert_token(ctx, ELSE);
+                       oberon_statement_seq(ctx);
+               }
+
+               oberon_generate_label(ctx, end);
+               oberon_assert_token(ctx, END);          
+       }
        else if(ctx -> token == RETURN)
        {
                oberon_assert_token(ctx, RETURN);