What do you think of this generator syntax?
- by ChaosPandion
I've been working on an ECMAScript dialect for quite some time now and have reached a point where I am comfortable adding new language features. I would love to hear some thoughts and suggestions on the syntax.
Example
generator {
yield 1;
yield 2;
yield 3;
if (true) {
yield break;
}
yield continue generator {
yield 4;
yield 5;
yield 6;
};
}
Syntax
GeneratorExpression:
generator { GeneratorBody }
GeneratorBody:
GeneratorStatementsopt
GeneratorStatements:
StatementListopt GeneratorStatement GeneratorStatementsopt
GeneratorStatement:
YieldStatement
YieldBreakStatement
YieldContinueStatement
YieldStatement:
yield Expression ;
YieldBreakStatement:
yield break ;
YieldContinueStatement:
yield continue Expression ;
Semantics
The YieldBreakStatement allows you to end iteration early. This helps avoid deeply indented code. You'll be able to write something like this:
generator {
yield something1();
if (condition1 && condition2)
yield break;
yield something2();
if (condition3 && condition4)
yield break;
yield something3();
}
instead of:
generator {
yield something1();
if (!condition1 && !condition2) {
yield something2();
if (!condition3 && !condition4) {
yield something3();
}
}
}
The YieldContinueStatement allows you to combine generators:
function generateNumbers(start) {
return generator {
yield 1 + start;
yield 2 + start;
yield 3 + start;
if (start < 100) {
yield continue generateNumbers(start + 1);
}
};
}
