Recursive Decent Parsing:Functions to parse the Toy Grammar I

This is the first of the four functions that parse the Toy Grammar. This first function handles the root non-terminal that is the root of the Parse Tree for this Grammar. All other productions reduce to this one.

• <> --> ID ‘=‘ <> ‘;’

assignment(){

if( tokentype != ID )

error(“Missing identifier”);

scanner(); /* get the next lookahead token */

if( tokentype != EQUALS )

error("Missing ‘=’");

scanner(); /* get the next lookahead token */

expression(); /* non-terminal is function call */

if( tokentype != SEMICOLON )

error("Missing ‘;’");

scanner(); /* get the next lookahead token */

}