// optimized {..., Then, Else } ==> {..., If }
this.astLengthPtr--;
//optimize the push/pop
this.astStack[--this.astPtr] =
new IfStatement(
this.expressionStack[this.expressionPtr--],
(Statement) this.astStack[this.astPtr],
(Statement) this.astStack[this.astPtr + 1],
this.intStack[this.intPtr--],
this.endStatementPosition);