From 069a6ef11c9423bdb2974b11823cc39743dfceec Mon Sep 17 00:00:00 2001
From: Karsten Schmidt <k@postspectacular.com>
Date: Mon, 20 Apr 2020 14:49:03 +0100
Subject: [PATCH] feat(parse): update ESC & whitespace parsers

---
 packages/parse/src/presets/escape.ts     | 20 ++++++++++++++++++--
 packages/parse/src/presets/whitespace.ts | 14 +++++++-------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/packages/parse/src/presets/escape.ts b/packages/parse/src/presets/escape.ts
index 263616a177..c761da1dad 100644
--- a/packages/parse/src/presets/escape.ts
+++ b/packages/parse/src/presets/escape.ts
@@ -1,14 +1,30 @@
 import { always } from "../prims/always";
 import { litD } from "../prims/lit";
 import { seq } from "../combinators/seq";
-import { hoist } from "../xform/hoist";
 import { xform } from "../combinators/xform";
 import { repeat } from "../combinators/repeat";
 import { HEX_DIGIT } from "./hex";
 import { stringD } from "../prims/string";
 import { xfInt } from "../xform/number";
+import { IObjectOf } from "@thi.ng/api";
 
-export const ESC = hoist(seq([litD("\\"), always()], "esc"));
+const ESC_VALUES: IObjectOf<string> = {
+    0: "\0",
+    b: "\b",
+    t: "\t",
+    n: "\n",
+    v: "\v",
+    f: "\f",
+    r: "\r",
+};
+
+export const ESC = xform(seq([litD("\\"), always()], "esc"), ($) => {
+    const id = $!.children![0].result;
+    const resolved = ESC_VALUES[id];
+    $!.result = resolved !== undefined ? resolved : id;
+    $!.children = null;
+    return $;
+});
 
 /**
  * Matches a single `\uNNNN` escaped unicode hex literal and transforms
diff --git a/packages/parse/src/presets/whitespace.ts b/packages/parse/src/presets/whitespace.ts
index a14f078d7c..72925c582b 100644
--- a/packages/parse/src/presets/whitespace.ts
+++ b/packages/parse/src/presets/whitespace.ts
@@ -1,11 +1,11 @@
-import { discard } from "../combinators/discard";
-import { oneOrMore, zeroOrMore } from "../combinators/repeat";
+import { WS as _WS } from "@thi.ng/strings";
+import { oneOrMoreD, zeroOrMoreD } from "../combinators/repeat";
 import { oneOf, oneOfD } from "../prims/one-of";
 
 /**
  * Matches & discards single whitespace char: ` \t\n\r`.
  */
-export const WS = oneOfD(" \t\n\r");
+export const WS = oneOfD(_WS);
 
 /**
  * Matches & discards single space or tab char.
@@ -25,19 +25,19 @@ export const DNL = oneOfD("\n\r");
 /**
  * Zero or more {@link WS}. Result will be discarded.
  */
-export const WS0 = discard(zeroOrMore(WS));
+export const WS0 = zeroOrMoreD(WS);
 
 /**
  * One or more {@link WS}. Result will be discarded.
  */
-export const WS1 = discard(oneOrMore(WS));
+export const WS1 = oneOrMoreD(WS);
 
 /**
  * Zero or more {@link SPACE}. Result will be discarded.
  */
-export const SPACES0 = discard(zeroOrMore(SPACE));
+export const SPACES0 = zeroOrMoreD(SPACE);
 
 /**
  * One or more {@link SPACE}. Result will be discarded.
  */
-export const SPACES = discard(oneOrMore(SPACE));
+export const SPACES = oneOrMoreD(SPACE);