cafe-grader-web

Location: cafe-grader-web/node_modules/dfa/index.js - annotation

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Commit Description:
add model solution
Commit Description:
add model solution
References:
r854:14d6c4fb29b0 default
File last commit:
r789:8cd7e8db7e38 default
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node_modules/dfa/index.js | 91 lines | 2.4 KiB | application/javascript | JavascriptLexer |
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move datatable to yarn
 r789 'use strict';
var INITIAL_STATE = 1;
var FAIL_STATE = 0;
/**
* A StateMachine represents a deterministic finite automaton.
* It can perform matches over a sequence of values, similar to a regular expression.
*/
class StateMachine {
constructor(dfa) {
this.stateTable = dfa.stateTable;
this.accepting = dfa.accepting;
this.tags = dfa.tags;
}
/**
* Returns an iterable object that yields pattern matches over the input sequence.
* Matches are of the form [startIndex, endIndex, tags].
*/
match(str) {
var self = this;
return {
*[Symbol.iterator]() {
var state = INITIAL_STATE;
var startRun = null;
var lastAccepting = null;
var lastState = null;
for (var p = 0; p < str.length; p++) {
var c = str[p];
lastState = state;
state = self.stateTable[state][c];
if (state === FAIL_STATE) {
// yield the last match if any
if (startRun != null && lastAccepting != null && lastAccepting >= startRun) {
yield [startRun, lastAccepting, self.tags[lastState]];
} // reset the state as if we started over from the initial state
state = self.stateTable[INITIAL_STATE][c];
startRun = null;
} // start a run if not in the failure state
if (state !== FAIL_STATE && startRun == null) {
startRun = p;
} // if accepting, mark the potential match end
if (self.accepting[state]) {
lastAccepting = p;
} // reset the state to the initial state if we get into the failure state
if (state === FAIL_STATE) {
state = INITIAL_STATE;
}
} // yield the last match if any
if (startRun != null && lastAccepting != null && lastAccepting >= startRun) {
yield [startRun, lastAccepting, self.tags[state]];
}
}
};
}
/**
* For each match over the input sequence, action functions matching
* the tag definitions in the input pattern are called with the startIndex,
* endIndex, and sub-match sequence.
*/
apply(str, actions) {
for (var [start, end, tags] of this.match(str)) {
for (var tag of tags) {
if (typeof actions[tag] === 'function') {
actions[tag](start, end, str.slice(start, end + 1));
}
}
}
}
}
module.exports = StateMachine;
//# sourceMappingURL=index.js.map