Initial revision

lang/m2/m2mm/statement.g

@@ -0,0 +1,136 @@
+/*
+ * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
+ * See the copyright notice in the ACK home directory, in the file "Copyright".
+ *
+ * Author: Ceriel J.H. Jacobs
+ */
+
+/* S T A T E M E N T S */
+
+/* stripped down version from the one in the Modula-2 compiler */
+
+/* $Header$ */
+
+{
+#include	"idf.h"
+#include	"LLlex.h"
+
+static int loopcount;
+}
+
+statement :
+[
+	/*
+	 * This part is not in the reference grammar. The reference grammar
+	 * states : assignment | ProcedureCall | ...
+	 * but this gives LL(1) conflicts
+	 */
+	designator
+	[
+		ActualParameters?
+	|
+		[ BECOMES	
+		| '='		{ error("':=' expected instead of '='");
+				  DOT = BECOMES;
+				}
+		]
+		expression
+	]
+	/*
+	 * end of changed part
+	 */
+|
+	IfStatement
+|
+	CaseStatement
+|
+	WHILE
+	expression
+	DO
+	StatementSequence
+	END
+|
+	REPEAT
+	StatementSequence
+	UNTIL
+	expression
+|
+				{ loopcount++; }
+	LOOP
+	StatementSequence
+	END
+				{ loopcount--; }
+|
+	ForStatement
+|
+	WithStatement
+|
+	EXIT
+			{ if (!loopcount) error("EXIT not in a LOOP"); }
+|
+	ReturnStatement
+|
+	/* empty */
+]
+;
+
+StatementSequence :
+	statement
+	[ %persistent
+		';'
+		statement
+	]*
+;
+
+IfStatement :
+	IF expression
+	THEN StatementSequence
+	[
+		ELSIF expression
+		THEN StatementSequence
+	]*
+	[
+		ELSE StatementSequence
+	]?
+	END
+;
+
+CaseStatement :
+	CASE expression
+	OF case
+	[
+		'|' case
+	]*
+	[ ELSE StatementSequence
+	]?
+	END
+;
+
+case :
+	[ CaseLabelList ':'
+	  StatementSequence
+	]?
+;
+
+ForStatement :
+	FOR IDENT BECOMES expression TO expression
+	[
+		BY ConstExpression
+	|
+	]
+	DO StatementSequence
+	END
+;
+
+WithStatement :
+	WITH designator DO StatementSequence
+	END
+;
+
+ReturnStatement :
+	RETURN
+	[
+		expression
+	|
+	]
+;