commit 7ec455083feef02deebb0e64d0e5414213ed4196
parent 40ec1b92b80f7e453b040287176fe5061b616786
Author: Martin von Gagern <gagern@ma.tum.de>
Date: Fri, 6 Jan 2017 18:52:50 +0100
Builtin macros, macro arguments, overset and underset
* Ship predefined macros with the library, in macros.js.
* Allow macro arguments #1 and so on, with argument count deduced from string.
* Use these features to implement \overset and \underset, fixes #484.
Diffstat:
5 files changed, 98 insertions(+), 3 deletions(-)
diff --git a/.eslintrc b/.eslintrc
@@ -39,7 +39,7 @@
"no-with": 2,
"one-var": [2, "never"],
"prefer-const": 2,
- "prefer-spread": 2,
+ "prefer-spread": 0, // re-enable once we use es6
"semi": [2, "always"],
"space-before-blocks": 2,
"space-before-function-paren": [2, "never"],
diff --git a/package.json b/package.json
@@ -30,6 +30,7 @@
"less": "~2.7.1",
"morgan": "^1.7.0",
"nomnom": "^1.8.1",
+ "object-assign": "^4.1.0",
"pako": "1.0.4",
"selenium-webdriver": "^2.48.2",
"sri-toolbox": "^0.2.0",
diff --git a/src/MacroExpander.js b/src/MacroExpander.js
@@ -4,10 +4,13 @@
*/
const Lexer = require("./Lexer");
+const builtinMacros = require("./macros");
+const ParseError = require("./ParseError");
+const objectAssign = require("object-assign");
function MacroExpander(input, macros) {
this.lexer = new Lexer(input);
- this.macros = macros;
+ this.macros = objectAssign({}, builtinMacros, macros);
this.stack = []; // contains tokens in REVERSE order
this.discardedWhiteSpace = [];
}
@@ -25,18 +28,87 @@ MacroExpander.prototype.nextToken = function() {
if (!(name.charAt(0) === "\\" && this.macros.hasOwnProperty(name))) {
return topToken;
}
+ let tok;
let expansion = this.macros[name];
if (typeof expansion === "string") {
+ let numArgs = 0;
+ if (expansion.indexOf("#") !== -1) {
+ const stripped = expansion.replace(/##/g, "");
+ while (stripped.indexOf("#" + (numArgs + 1)) !== -1) {
+ ++numArgs;
+ }
+ }
const bodyLexer = new Lexer(expansion);
expansion = [];
- let tok = bodyLexer.lex();
+ tok = bodyLexer.lex();
while (tok.text !== "EOF") {
expansion.push(tok);
tok = bodyLexer.lex();
}
expansion.reverse(); // to fit in with stack using push and pop
+ expansion.numArgs = numArgs;
this.macros[name] = expansion;
}
+ if (expansion.numArgs) {
+ const args = [];
+ let i;
+ // obtain arguments, either single token or balanced {…} group
+ for (i = 0; i < expansion.numArgs; ++i) {
+ const startOfArg = this.get(true);
+ if (startOfArg.text === "{") {
+ const arg = [];
+ let depth = 1;
+ while (depth !== 0) {
+ tok = this.get(false);
+ arg.push(tok);
+ if (tok.text === "{") {
+ ++depth;
+ } else if (tok.text === "}") {
+ --depth;
+ } else if (tok.text === "EOF") {
+ throw new ParseError(
+ "End of input in macro argument",
+ startOfArg);
+ }
+ }
+ arg.pop(); // remove last }
+ arg.reverse(); // like above, to fit in with stack order
+ args[i] = arg;
+ } else if (startOfArg.text === "EOF") {
+ throw new ParseError(
+ "End of input expecting macro argument", topToken);
+ } else {
+ args[i] = [startOfArg];
+ }
+ }
+ // paste arguments in place of the placeholders
+ expansion = expansion.slice(); // make a shallow copy
+ for (i = expansion.length - 1; i >= 0; --i) {
+ tok = expansion[i];
+ if (tok.text === "#") {
+ if (i === 0) {
+ throw new ParseError(
+ "Incomplete placeholder at end of macro body",
+ tok);
+ }
+ tok = expansion[--i]; // next token on stack
+ if (tok.text === "#") { // ## → #
+ expansion.splice(i + 1, 1); // drop first #
+ } else if (/^[1-9]$/.test(tok.text)) {
+ // expansion.splice(i, 2, arg[0], arg[1], …)
+ // to replace placeholder with the indicated argument.
+ // TODO: use spread once we move to ES2015
+ expansion.splice.apply(
+ expansion,
+ [i, 2].concat(args[tok.text - 1]));
+ } else {
+ throw new ParseError(
+ "Not a valid argument number",
+ tok);
+ }
+ }
+ }
+ }
this.stack = this.stack.concat(expansion);
}
};
diff --git a/src/macros.js b/src/macros.js
@@ -0,0 +1,15 @@
+/**
+ * Predefined macros for KaTeX.
+ * This can be used to define some commands in terms of others.
+ */
+
+module.exports = {
+
+ //////////////////////////////////////////////////////////////////////
+ // amsmath.sty
+
+ // \def\overset#1#2{\binrel@{#2}\binrel@@{\mathop{\kern\z@#2}\limits^{#1}}}
+ "\\overset": "\\mathop{#2}\\limits^{#1}",
+ "\\underset": "\\mathop{#2}\\limits_{#1}",
+
+};
diff --git a/test/katex-spec.js b/test/katex-spec.js
@@ -2011,6 +2011,13 @@ describe("A macro expander", function() {
"\\bar": "a",
});
});
+
+ it("should expand the \overset macro as expected", function() {
+ expect("\\overset?=").toParseLike("\\mathop{=}\\limits^{?}");
+ expect("\\overset{x=y}{\sqrt{ab}}")
+ .toParseLike("\\mathop{\sqrt{ab}}\\limits^{x=y}");
+ expect("\\overset {?} =").toParseLike("\\mathop{=}\\limits^{?}");
+ });
});
describe("A parser taking String objects", function() {
