/* eslint-disable func-names */
/* eslint-disable new-cap */
/* *************************************************************************************
* copyright: Copyright (c) 2021 Lowell D. Thomas, all rights reserved
* license: BSD-2-Clause (https://opensource.org/licenses/BSD-2-Clause)
* ********************************************************************************* */This is the general set up for demonstrating both
the translation and XML display of the AST.
module.exports = function setup() {
const nodeUtil = require('node:util');
const grammar = new (require('./phone-number'))();
const inspectOptions = {
showHidden: true,
depth: null,
};
try {
/* Acquire the required parser components. */
const apgJs = require('apg-js');
const { apgLib } = apgJs;
const parser = new apgLib.parser();
/* Construct an `AST` object and attach it to the parser. */
parser.ast = new apgLib.ast();
const id = apgLib.ids;The AST translating callback functions. These are similar to the parsers syntax callback functions
in that they are each called twice, once down the tree and once up the tree, with matched phrase information.
With the AST, however, the matched phrase is known in the down direction as well as up.
SEM_PRE (down) or SEM_POST (up)SEM_OK. Can also be SEM_SKIP in the SEM_PRE
state to skip the translation of the branch below the current node. const phoneNumber = function (state, chars, phraseIndex, phraseLength, data) {
const ret = id.SEM_OK;
if (state === id.SEM_PRE) {
if (Array.isArray(data) === false) {
throw new Error("parser's user data must be an array");
}
data.length = 0;
} else if (state === id.SEM_POST) {
/* not used in this example */
}
return ret;
};
const areaCode = function (state, chars, phraseIndex, phraseLength, data) {
const ret = id.SEM_OK;
if (state === id.SEM_PRE) {
data['area-code'] = apgLib.utils.charsToString(chars, phraseIndex, phraseLength);
} else if (state === id.SEM_POST) {
/* not used in this example */
}
return ret;
};
const office = function (state, chars, phraseIndex, phraseLength, data) {
const ret = id.SEM_OK;
if (state === id.SEM_PRE) {
data.office = apgLib.utils.charsToString(chars, phraseIndex, phraseLength);
} else if (state === id.SEM_POST) {
/* not used in this example */
}
return ret;
};
const subscriber = function (state, chars, phraseIndex, phraseLength, data) {
const ret = id.SEM_OK;
if (state === id.SEM_PRE) {
data.subscriber = apgLib.utils.charsToString(chars, phraseIndex, phraseLength);
} else if (state === id.SEM_POST) {
/* not used in this example */
}
return ret;
};Attach the callback functions to the AST.
parser.ast.callbacks['phone-number'] = phoneNumber;
parser.ast.callbacks['area-code'] = areaCode;
parser.ast.callbacks.office = office;
parser.ast.callbacks.subscriber = subscriber;
/* use a hard coded input string */
const inputString = 'xxxx(555)234-5678xxxx';
const inputCharacterCodes = apgLib.utils.stringToChars(inputString);
const startRule = 'phone-number';
/* parse the string here, generating an `AST` */
const result = parser.parseSubstring(grammar, startRule, inputCharacterCodes, 4, 13);
console.log();
console.log("the parser's results");
console.dir(result, inspectOptions);
if (result.success === false) {
throw new Error(`input string: '${inputString}' : parse failed`);
}
/* Return the `AST` object for further processing. */
return parser.ast;
} catch (e) {
let msg = '\nEXCEPTION THROWN: \n';
if (e instanceof Error) {
msg += `${e.name}: ${e.message}`;
} else if (typeof e === 'string') {
msg += e;
} else {
msg += nodeUtil.inspect(e, inspectOptions);
}
process.exitCode = 1;
console.log(msg);
throw e;
}
};