flow2schema/src/collector/pragmas.js

// @flow

import {invariant} from '../utils';

import type {Type} from '../types';
import {createNumber, isRepr} from '../types';

export type Pragma =
    | TypePragma
    ;

export type TypePragma = {
    kind: 'type',
    value: Type,
};

const PRAGMA_RE = /^\s*@repr\s+\{\s*(.+?)\s*\}\s*$/gm;

export function extractPragmas(text: string): Pragma[] {
    const pragmas = [];
    let match;

    while ((match = PRAGMA_RE.exec(text))) {
        const repr = match[1];

        invariant(isRepr(repr));

        pragmas.push({
            kind: 'type',
            value: createNumber(repr),
        });
    }

    return pragmas;
}