74 lines
No EOL
1.1 KiB
JavaScript
74 lines
No EOL
1.1 KiB
JavaScript
/**
|
|
* The MIT License (MIT)
|
|
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
|
|
*/
|
|
|
|
'use strict';
|
|
|
|
/**
|
|
* A regexp-tree plugin to replace different range-based quantifiers
|
|
* with their symbol equivalents.
|
|
*
|
|
* a{0,} -> a*
|
|
* a{1,} -> a+
|
|
* a{1} -> a
|
|
*
|
|
* NOTE: the following is automatically handled in the generator:
|
|
*
|
|
* a{3,3} -> a{3}
|
|
*/
|
|
|
|
module.exports = {
|
|
Quantifier: function Quantifier(path) {
|
|
var node = path.node;
|
|
|
|
|
|
if (node.kind !== 'Range') {
|
|
return;
|
|
}
|
|
|
|
// a{0,} -> a*
|
|
rewriteOpenZero(path);
|
|
|
|
// a{1,} -> a+
|
|
rewriteOpenOne(path);
|
|
|
|
// a{1} -> a
|
|
rewriteExactOne(path);
|
|
}
|
|
};
|
|
|
|
function rewriteOpenZero(path) {
|
|
var node = path.node;
|
|
|
|
|
|
if (node.from !== 0 || node.to) {
|
|
return;
|
|
}
|
|
|
|
node.kind = '*';
|
|
delete node.from;
|
|
}
|
|
|
|
function rewriteOpenOne(path) {
|
|
var node = path.node;
|
|
|
|
|
|
if (node.from !== 1 || node.to) {
|
|
return;
|
|
}
|
|
|
|
node.kind = '+';
|
|
delete node.from;
|
|
}
|
|
|
|
function rewriteExactOne(path) {
|
|
var node = path.node;
|
|
|
|
|
|
if (node.from !== 1 || node.to !== 1) {
|
|
return;
|
|
}
|
|
|
|
path.parentPath.replace(path.parentPath.node.expression);
|
|
} |