Files
st/data/st-core-scripts/scripts/macros/engine/MacroCstWalker.js

434 lines
15 KiB
JavaScript

/** @typedef {import('chevrotain').CstNode} CstNode */
/** @typedef {import('chevrotain').IToken} IToken */
/** @typedef {import('./MacroEnv.types.js').MacroEnv} MacroEnv */
/**
* @typedef {Object} MacroCall
* @property {string} name
* @property {string[]} args
* @property {MacroEnv} env
* @property {string} rawInner
* @property {string} rawWithBraces
* @property {{ startOffset: number, endOffset: number }} range
* @property {CstNode} cstNode
*/
/**
* @typedef {Object} EvaluationContext
* @property {string} text
* @property {MacroEnv} env
* @property {(call: MacroCall) => string} resolveMacro
*/
/**
* @typedef {Object} TokenRange
* @property {number} startOffset
* @property {number} endOffset
*/
/**
* The singleton instance of the MacroCstWalker.
*
* @type {MacroCstWalker}
*/
let instance;
export { instance as MacroCstWalker };
class MacroCstWalker {
/** @type {MacroCstWalker} */ static #instance;
/** @type {MacroCstWalker} */ static get instance() { return MacroCstWalker.#instance ?? (MacroCstWalker.#instance = new MacroCstWalker()); }
constructor() { }
/**
* Evaluates a full document CST into a resolved string.
*
* @param {EvaluationContext & { cst: CstNode }} options
* @returns {string}
*/
evaluateDocument(options) {
const { text, cst, env, resolveMacro } = options;
if (typeof text !== 'string') {
throw new Error('MacroCstWalker.evaluateDocument: text must be a string');
}
if (!cst || typeof cst !== 'object' || !cst.children) {
throw new Error('MacroCstWalker.evaluateDocument: cst must be a CstNode');
}
if (typeof resolveMacro !== 'function') {
throw new Error('MacroCstWalker.evaluateDocument: resolveMacro must be a function');
}
/** @type {EvaluationContext} */
const context = { text, env, resolveMacro };
const items = this.#collectDocumentItems(cst);
if (items.length === 0) {
return text;
}
let result = '';
let cursor = 0;
// Iterate over all items in the document. Evaluate any macro being found, and keep them in the exact same place.
for (const item of items) {
if (item.startOffset > cursor) {
result += text.slice(cursor, item.startOffset);
}
// Items can be either plaintext or macro nodes
if (item.type === 'plaintext') {
result += text.slice(item.startOffset, item.endOffset + 1);
} else {
result += this.#evaluateMacroNode(item.node, context);
}
cursor = item.endOffset + 1;
}
if (cursor < text.length) {
result += text.slice(cursor);
}
return result;
}
/** @typedef {{ type: 'plaintext', startOffset: number, endOffset: number, token: IToken }} DocumentItemPlaintext */
/** @typedef {{ type: 'macro', startOffset: number, endOffset: number, node: CstNode }} DocumentItemMacro */
/** @typedef {DocumentItemPlaintext | DocumentItemMacro} DocumentItem */
/**
* Collects top-level plaintext tokens and macro nodes from the document CST.
*
* @param {CstNode} cst
* @returns {Array<DocumentItem>}
*/
#collectDocumentItems(cst) {
const plaintextTokens = /** @type {IToken[]} */ (cst.children.plaintext || []);
const macroNodes = /** @type {CstNode[]} */ (cst.children.macro || []);
/** @type {Array<DocumentItem>} */
const items = [];
for (const token of plaintextTokens) {
if (typeof token.startOffset !== 'number' || typeof token.endOffset !== 'number') {
continue;
}
items.push({
type: 'plaintext',
startOffset: token.startOffset,
endOffset: token.endOffset,
token,
});
}
for (const macroNode of macroNodes) {
const children = macroNode.children || {};
const endToken = /** @type {IToken?} */ ((children['Macro.End'] || [])[0]);
// If the end token was inserted during error recovery, treat this macro as plaintext
if (this.#isRecoveryToken(endToken)) {
// Flatten the incomplete macro: collect its tokens as plaintext but keep nested macros
this.#flattenIncompleteMacro(macroNode, endToken, items);
continue;
}
const range = this.#getMacroRange(macroNode);
items.push({
type: 'macro',
startOffset: range.startOffset,
endOffset: range.endOffset,
node: macroNode,
});
}
items.sort((a, b) => {
if (a.startOffset !== b.startOffset) {
return a.startOffset - b.startOffset;
}
return a.endOffset - b.endOffset;
});
return items;
}
/**
* Evaluates a single macro CST node, resolving any nested macros first.
*
* @param {CstNode} macroNode
* @param {EvaluationContext} context
* @returns {string}
*/
#evaluateMacroNode(macroNode, context) {
const { text, env, resolveMacro } = context;
const children = macroNode.children || {};
const identifierTokens = /** @type {IToken[]} */ (children['Macro.identifier'] || []);
const name = identifierTokens[0]?.image || '';
const range = this.#getMacroRange(macroNode);
const startToken = /** @type {IToken?} */ ((children['Macro.Start'] || [])[0]);
const endToken = /** @type {IToken?} */ ((children['Macro.End'] || [])[0]);
const innerStart = startToken ? startToken.endOffset + 1 : range.startOffset;
const innerEnd = endToken ? endToken.startOffset - 1 : range.endOffset;
// Extract argument nodes from the "arguments" rule (if present)
const argumentsNode = /** @type {CstNode?} */ ((children.arguments || [])[0]);
const argumentNodes = /** @type {CstNode[]} */ (argumentsNode?.children?.argument || []);
/** @type {string[]} */
const args = [];
/** @type {({ value: string } & TokenRange)[]} */
const evaluatedArguments = [];
for (const argNode of argumentNodes) {
const argValue = this.#evaluateArgumentNode(argNode, context);
args.push(argValue);
const location = this.#getArgumentLocation(argNode);
if (location) {
evaluatedArguments.push({
value: argValue,
...location,
});
}
}
evaluatedArguments.sort((a, b) => a.startOffset - b.startOffset);
// Build the inner raw string between the braces, with nested macros resolved.
// This uses the already evaluated argument strings and preserves any text
// between arguments (such as separators or whitespace).
let rawInner = '';
if (innerStart <= innerEnd) {
let cursor = innerStart;
for (const entry of evaluatedArguments) {
if (entry.startOffset > cursor) {
rawInner += text.slice(cursor, entry.startOffset);
}
rawInner += entry.value;
cursor = entry.endOffset + 1;
}
if (cursor <= innerEnd) {
rawInner += text.slice(cursor, innerEnd + 1);
}
}
/** @type {MacroCall} */
const call = {
name,
args,
rawInner,
rawWithBraces: text.slice(range.startOffset, range.endOffset + 1),
range,
cstNode: macroNode,
env,
};
const value = resolveMacro(call);
const stringValue = typeof value === 'string' ? value : String(value ?? '');
return stringValue;
}
/**
* Evaluates a single argument node by resolving nested macros and reconstructing
* the original argument text.
*
* @param {CstNode} argNode
* @param {EvaluationContext} context
* @returns {string}
*/
#evaluateArgumentNode(argNode, context) {
const location = this.#getArgumentLocation(argNode);
if (!location) {
return '';
}
const { text } = context;
const nestedMacros = /** @type {CstNode[]} */ ((argNode.children || {}).macro || []);
// If there are no nested macros, we can just return the original text
if (nestedMacros.length === 0) {
return text.slice(location.startOffset, location.endOffset + 1);
}
// If there are macros, evaluate them one by one in appearing order, inside the argument, before we return the resolved argument
const nestedWithRange = nestedMacros.map(node => ({
node,
range: this.#getMacroRange(node),
}));
nestedWithRange.sort((a, b) => a.range.startOffset - b.range.startOffset);
let result = '';
let cursor = location.startOffset;
for (const entry of nestedWithRange) {
if (entry.range.startOffset < cursor) {
continue;
}
result += text.slice(cursor, entry.range.startOffset);
result += this.#evaluateMacroNode(entry.node, context);
cursor = entry.range.endOffset + 1;
}
if (cursor <= location.endOffset) {
result += text.slice(cursor, location.endOffset + 1);
}
return result;
}
/**
* Computes the character range of a macro node based on its start/end tokens
* or its own location if those are not available.
*
* @param {CstNode} macroNode
* @returns {TokenRange}
*/
#getMacroRange(macroNode) {
const startToken = /** @type {IToken?} */ (((macroNode.children || {})['Macro.Start'] || [])[0]);
const endToken = /** @type {IToken?} */ (((macroNode.children || {})['Macro.End'] || [])[0]);
if (startToken && endToken) {
return { startOffset: startToken.startOffset, endOffset: endToken.endOffset };
}
if (macroNode.location) {
return { startOffset: macroNode.location.startOffset, endOffset: macroNode.location.endOffset };
}
return { startOffset: 0, endOffset: 0 };
}
/**
* Flattens an incomplete macro node into document items.
* Tokens from the incomplete macro become plaintext, but nested complete macros are preserved.
*
* @param {CstNode} macroNode
* @param {IToken} excludeToken - The recovery-inserted token to exclude
* @param {Array<DocumentItem>} items - The items array to add to
*/
#flattenIncompleteMacro(macroNode, excludeToken, items) {
const children = macroNode.children || {};
for (const key of Object.keys(children)) {
for (const element of children[key] || []) {
// Skip the recovery-inserted token
if (element === excludeToken) continue;
// Handle IToken - add as plaintext
if ('startOffset' in element && typeof element.startOffset === 'number') {
items.push({
type: 'plaintext',
startOffset: element.startOffset,
endOffset: element.endOffset ?? element.startOffset,
token: element,
});
}
// Handle nested CstNode (macro or argument)
else if ('children' in element) {
const nestedChildren = element.children || {};
const nestedEnd = /** @type {IToken?} */ ((nestedChildren['Macro.End'] || [])[0]);
const nestedStart = /** @type {IToken?} */ ((nestedChildren['Macro.Start'] || [])[0]);
// Check if this is a complete macro node
if (nestedStart && nestedEnd) {
if (!this.#isRecoveryToken(nestedEnd)) {
// Complete nested macro - add as macro item
const range = this.#getMacroRange(element);
items.push({
type: 'macro',
startOffset: range.startOffset,
endOffset: range.endOffset,
node: element,
});
} else {
// Another incomplete nested macro - recurse
this.#flattenIncompleteMacro(element, nestedEnd, items);
}
} else {
// Not a macro node (e.g., arguments, argument) - recurse into it
this.#flattenIncompleteMacro(element, excludeToken, items);
}
}
}
}
}
/**
* Checks if a token was inserted during Chevrotain's error recovery.
* Recovery tokens have `isInsertedInRecovery=true` or invalid offset values.
*
* @param {IToken|null|undefined} token
* @returns {boolean}
*/
#isRecoveryToken(token) {
return token?.isInsertedInRecovery === true
|| typeof token?.startOffset !== 'number'
|| Number.isNaN(token?.startOffset);
}
/**
* Computes the character range of an argument node based on all its child
* tokens and nested macros.
*
* @param {CstNode} argNode
* @returns {TokenRange|null}
*/
#getArgumentLocation(argNode) {
const children = argNode.children || {};
let startOffset = Number.POSITIVE_INFINITY;
let endOffset = Number.NEGATIVE_INFINITY;
for (const key of Object.keys(children)) {
for (const element of children[key] || []) {
if (this.#isCstNode(element)) {
const location = element.location;
if (!location) {
continue;
}
if (location.startOffset < startOffset) {
startOffset = location.startOffset;
}
if (location.endOffset > endOffset) {
endOffset = location.endOffset;
}
} else if (element) {
if (element.startOffset < startOffset) {
startOffset = element.startOffset;
}
if (element.endOffset > endOffset) {
endOffset = element.endOffset;
}
}
}
}
if (!Number.isFinite(startOffset) || !Number.isFinite(endOffset)) {
return null;
}
return { startOffset, endOffset };
}
/**
* Determines whether the given value is a CST node.
*
* @param {any} value
* @returns {value is CstNode}
*/
#isCstNode(value) {
return !!value && typeof value === 'object' && 'name' in value && 'children' in value;
}
}
instance = MacroCstWalker.instance;