Error: Illegal #include (Preprocessor.js:225)

[markusha]

1. Create a file test.js with the following content:

// #ifndef TEST
// #define var TEST=true
console.log('test');
// #endif

1. Create a file main.js with the following content:

// #include "test.js"
console.log('testing include');
// #include "test.js"

1. Preprocess main.js.

Result:
The file test.js is included twice in the output file.
The following error is shown:

C:\programs\nodejs\node_modules\preprocessor\Preprocessor.js:225
                        throw(new Error("Illegal #"+match[2]+": "+this.source.
                              ^
Error: Illegal #include: // #include "test.js
...
    at Preprocessor.process (C:\programs\nodejs\node_modules\preprocessor\Preprocessor.js:225:31)
    at Object.<anonymous> (C:\programs\nodejs\node_modules\preprocessor\bin\preprocess:65:16)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:906:3

Expected result:
The file test.js is included only once in the output file.
No errors are shown.

P. S. I see that there's an undocumented directive #include_once for such cases. But still this is an error.

[markusha]

My bad. The error was shown due to my slow typing/quick reaction of a script that runs the preprocessor.
But still the file test.js was included twice in the output file.

[dcodeIO]

Maybe I miss something, but for a main.js with contents

// #include "test.js"
console.log('testing include');
// #include "test.js"

the file test.js is of course included twice, while for

// #include_once "test.js"
console.log('testing include');
// #include_once "test.js"

it's not.

[markusha]

Ah, again my bad for not specifically describing the problem.
The file test.js in this case must indeed be included in main.js twice. But the thing is that the contents of the file test.js, specifically console.log('test');, will be included twice too. Which is an error because #ifndef from the second inclusion must prevent this.

[dcodeIO]

I see. Well, the issue here is that #define is quite a hack currently and does not play well with #ifdef, which is of course bad and I'd need to invest some time to rethink both.

Personally, I am migrating all my projects to MetaScript currently (e.g. https://github.com/dcodeIO/ByteBuffer.js/tree/master/src), which is a more javascripty way of preprocessing, and I'd recommend that you'd do the same.

test.js

//? if (typeof TEST === 'undefined') { TEST = true;
console.log("test");
//? }

main.js

//? include("test.js");
console.log('testing include');
//? include("test.js");

which does exactly what you need.

[markusha]

Personally, I am migrating all my projects to MetaScript

Thanks for the tip.