Commit node_modules

paige/node_modules/katex/src/defineEnvironment.js

@@ -0,0 +1,117 @@
+// @flow
+import {_htmlGroupBuilders, _mathmlGroupBuilders} from "./defineFunction";
+
+import type Parser from "./Parser";
+import type {AnyParseNode} from "./parseNode";
+import type {ArgType, Mode} from "./types";
+import type {NodeType} from "./parseNode";
+import type {HtmlBuilder, MathMLBuilder} from "./defineFunction";
+
+/**
+ * The context contains the following properties:
+ *  - mode: current parsing mode.
+ *  - envName: the name of the environment, one of the listed names.
+ *  - parser: the parser object.
+ */
+type EnvContext = {|
+    mode: Mode,
+    envName: string,
+    parser: Parser,
+|};
+
+/**
+ *  - context: information and references provided by the parser
+ *  - args: an array of arguments passed to \begin{name}
+ *  - optArgs: an array of optional arguments passed to \begin{name}
+ */
+type EnvHandler = (
+    context: EnvContext,
+    args: AnyParseNode[],
+    optArgs: (?AnyParseNode)[],
+) => AnyParseNode;
+
+/**
+ *  - numArgs: (default 0) The number of arguments after the \begin{name} function.
+ *  - argTypes: (optional) Just like for a function
+ *  - allowedInText: (default false) Whether or not the environment is allowed
+ *                   inside text mode (not enforced yet).
+ *  - numOptionalArgs: (default 0) Just like for a function
+ */
+type EnvProps = {
+    numArgs: number,
+};
+
+/**
+ * Final enviornment spec for use at parse time.
+ * This is almost identical to `EnvDefSpec`, except it
+ * 1. includes the function handler
+ * 2. requires all arguments except argType
+ * It is generated by `defineEnvironment()` below.
+ */
+export type EnvSpec<NODETYPE: NodeType> = {|
+    type: NODETYPE, // Need to use the type to avoid error. See NOTES below.
+    numArgs: number,
+    argTypes?: ArgType[],
+    allowedInText: boolean,
+    numOptionalArgs: number,
+    handler: EnvHandler,
+|};
+
+/**
+ * All registered environments.
+ * `environments.js` exports this same dictionary again and makes it public.
+ * `Parser.js` requires this dictionary via `environments.js`.
+ */
+export const _environments: {[string]: EnvSpec<*>} = {};
+
+type EnvDefSpec<NODETYPE: NodeType> = {|
+    // Unique string to differentiate parse nodes.
+    type: NODETYPE,
+
+    // List of functions which use the give handler, htmlBuilder,
+    // and mathmlBuilder.
+    names: Array<string>,
+
+    // Properties that control how the environments are parsed.
+    props: EnvProps,
+
+    handler: EnvHandler,
+
+    // This function returns an object representing the DOM structure to be
+    // created when rendering the defined LaTeX function.
+    htmlBuilder: HtmlBuilder<NODETYPE>,
+
+    // This function returns an object representing the MathML structure to be
+    // created when rendering the defined LaTeX function.
+    mathmlBuilder: MathMLBuilder<NODETYPE>,
+|};
+
+export default function defineEnvironment<NODETYPE: NodeType>({
+    type,
+    names,
+    props,
+    handler,
+    htmlBuilder,
+    mathmlBuilder,
+}: EnvDefSpec<NODETYPE>) {
+    // Set default values of environments.
+    const data = {
+        type,
+        numArgs: props.numArgs || 0,
+        allowedInText: false,
+        numOptionalArgs: 0,
+        handler,
+    };
+    for (let i = 0; i < names.length; ++i) {
+        // TODO: The value type of _environments should be a type union of all
+        // possible `EnvSpec<>` possibilities instead of `EnvSpec<*>`, which is
+        // an existential type.
+        _environments[names[i]] = data;
+    }
+    if (htmlBuilder) {
+        _htmlGroupBuilders[type] = htmlBuilder;
+    }
+    if (mathmlBuilder) {
+        _mathmlGroupBuilders[type] = mathmlBuilder;
+    }
+}