Make shorter skip

Author: dy

feature/comment.js

@@ -3,5 +3,5 @@ import { token, skip, next, cur, idx, expr } from "../src/parse.js"
 
 // /**/, //
 // FIXME: try replacing with group
-token('/*', PREC_TOKEN, (a, prec) => (next(c => c !== STAR && cur.charCodeAt(idx + 1) !== 47), skip(2), a || expr(prec) || []))
+token('/*', PREC_TOKEN, (a, prec) => (next(c => c !== STAR && cur.charCodeAt(idx + 1) !== 47), skip(),skip(), a || expr(prec) || []))
 token('//', PREC_TOKEN, (a, prec) => (next(c => c >= SPACE), a || expr(prec) || []))

feature/number.js

@@ -1,4 +1,4 @@
-import { lookup, next, skip, err, cur, idx } from "../src/parse.js"
+import { lookup, next, err } from "../src/parse.js"
 import { PERIOD, _0, _E, _e, _9 } from "../src/const.js"
 
 // parse number

feature/string.js

@@ -1,14 +1,15 @@
-import { skip, err, cur, idx, lookup } from '../src/parse.js'
+import { skip, err, next, cur, idx, lookup } from '../src/parse.js'
 import { DQUOTE, QUOTE, BSLASH } from '../src/const.js'
 
 const escape = { n: '\n', r: '\r', t: '\t', b: '\b', f: '\f', v: '\v' },
-  string = q => (qc, c, str = '') => {
+  string = q => (qc, prec, str = '') => {
     qc && err('Unexpected string') // must not follow another token
-    skip() // first quote
-    while (c = cur.charCodeAt(idx), c - q) {
-      if (c === BSLASH) skip(), c = skip(), str += escape[c] || c
-      else str += skip()
-    }
+    skip()
+    // while (c = cur.charCodeAt(idx), c - q) {
+    //   if (c === BSLASH) skip(), c = cur[idx], skip(), str += escape[c] || c
+    //   else str += cur[idx], skip()
+    // }
+    next(c => c - q && (c === BSLASH ? (str += escape[cur[idx+1]] || cur[idx+1], 2 ) : (str += cur[idx], 1)))
     skip() || err('Bad string')
     return [, str]
   }

src/parse.d.ts

@@ -6,7 +6,7 @@ export namespace parse {
   function id(n: any): any;
 }
 export function err(msg?: string, frag?: string): never;
-export function skip(n: number): string;
+export function skip(): string;
 export function next(is: ((c: number) => number)): string;
 export const lookup: ((a: any, b: any) => any)[];
 export function token(op: string, prec: number, map: (a: any, curPrec: number, from: number) => any): (a: any, curPrec: number, from?: any) => any;

src/parse.js

@@ -22,8 +22,8 @@ export let idx, cur,
     return cur.slice(from, idx)
   },
 
-  // consume n characters
-  skip = (n = 1, from = idx) => (idx += n, cur.slice(from, idx)),
+  // advance n characters
+  skip = () => cur[idx++],
 
   // a + b - c
   expr = (prec = 0, end) => {