git.kianting.info Git - clo/blob - src/index.ts

   1 var fs = require('fs');
   2
   3 import * as tk from './tokenize.js';
   4
   5
   6
   7 let b : Array<tk.Token> = tk.tokenize("2+2");
   8
   9 export interface TokenMatcheePair {
  10     matched: tk.Token[]
  11     remained: tk.Token[]
  12 }
  13
  14 /**
  15  * @description
  16  * it returns a function which test if the first char of the `remained` part of
  17  *  the argument of the function is `c`, if it's true, update the `MatchedPair` wrapped
  18  * in `Some`. Otherwise, it returns `None`.
  19  *  * @param t : the char to be test.
  20  * @returns the updated `MatchedPair` wrapped in `Some(x)` or `None`.
  21  */
  22 export function match1token(t: tk.Token): (m: TokenMatcheePair) => tk.Maybe<TokenMatcheePair> {
  23     return (m: TokenMatcheePair) => {
  24         if (m.remained.length == 0) {
  25             return { _tag: "None" };
  26         }
  27         const tokenToBeMatched = m.remained[0];
  28         if (tokenToBeMatched === t) {
  29             m.matched.push(tokenToBeMatched);
  30             return {
  31                 _tag: "Some", value: {
  32                     matched: m.matched,
  33                     remained: m.remained.slice(1)
  34                 }
  35             };
  36         }
  37         else {
  38             return { _tag: "None" };
  39         }
  40     }
  41 };
  42
  43
  44
  45 let c = tk.toSome(b);
  46 console.log(thenDo(c,match1token(tk.tokenize("+")[0])));