From 1ff25424db5caccb6f836b482c36de114ddefd8e Mon Sep 17 00:00:00 2001
From: Louis-Dominique Dubeau <ldd@lddubeau.com>
Date: Mon, 24 Jun 2019 19:16:45 -0400
Subject: [PATCH] feat: add support for the RestrictedChar production

---
 src/xml/1.1/ed2.ts    | 21 +++++++++++++++++++++
 test/xmlchars.spec.ts |  9 +++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/xml/1.1/ed2.ts b/src/xml/1.1/ed2.ts
index a75d46d..4aa6cde 100644
--- a/src/xml/1.1/ed2.ts
+++ b/src/xml/1.1/ed2.ts
@@ -11,6 +11,9 @@
 //
 export const CHAR = "\u0001-\uD7FF\uE000-\uFFFD\u{10000}-\u{10FFFF}";
 
+export const RESTRICTED_CHAR =
+  "\u0001-\u0008\u000B\u000C\u000E-\u001F\u007F-\u0084\u0086-\u009F";
+
 export const S = " \t\r\n";
 
 // tslint:disable-next-line:max-line-length
@@ -25,6 +28,8 @@ export const NAME_CHAR =
 
 export const CHAR_RE = new RegExp(`^[${CHAR}]$`, "u");
 
+export const RESTRICTED_CHAR_RE = new RegExp(`^[${RESTRICTED_CHAR}]$`, "u");
+
 export const S_RE = new RegExp(`^[${S}]+$`, "u");
 
 export const NAME_START_CHAR_RE = new RegExp(`^[${NAME_START_CHAR}]$`, "u");
@@ -60,6 +65,22 @@ export function isChar(c: number): boolean {
     (c >= 0x10000 && c <= 0x10FFFF);
 }
 
+/**
+ * Determines whether a codepoint matches the ``RESTRICTED_CHAR`` production.
+ *
+ * @param c The code point.
+ *
+ * @returns ``true`` if the codepoint matches ``RESTRICTED_CHAR``.
+ */
+export function isRestrictedChar(c: number): boolean {
+  return (c >= 0x1 && c <= 0x8) ||
+    c === 0xB ||
+    c === 0xC ||
+    (c >= 0xE && c <= 0x1F) ||
+    (c >= 0x7F && c <= 0x84) ||
+    (c >= 0x86 && c <= 0x9F);
+}
+
 /**
  * Determines whether a codepoint matches the ``S`` (space) production.
  *
diff --git a/test/xmlchars.spec.ts b/test/xmlchars.spec.ts
index d58d7b7..5752b9f 100644
--- a/test/xmlchars.spec.ts
+++ b/test/xmlchars.spec.ts
@@ -303,6 +303,9 @@ describe("xml/1.1", () => {
         matching: [one, x, poo, colon, space, tab, newline, cr, ideographic,
                    combining, digit, extender],
       },
+      RESTRICTED_CHAR_RE: {
+        matching: [one],
+      },
       S_RE: {
         matching: [space, tab, newline, cr],
       },
@@ -336,6 +339,12 @@ describe("xml/1.1", () => {
       makeCodePointTestTests(xml_1_1_ed2.isChar, cases.CHAR_RE);
     });
 
+    describe(".isRestrictedChar", () => {
+      // tslint:disable-next-line:mocha-no-side-effect-code
+      makeCodePointTestTests(xml_1_1_ed2.isRestrictedChar,
+                             cases.RESTRICTED_CHAR_RE);
+    });
+
     describe(".isS", () => {
       // tslint:disable-next-line:mocha-no-side-effect-code
       makeCodePointTestTests(xml_1_1_ed2.isS, cases.S_RE);