/* *************************************************************************************
* copyright: Copyright (c) 2021 Lowell D. Thomas, all rights reserved
* license: BSD-2-Clause (https://opensource.org/licenses/BSD-2-Clause)
* ********************************************************************************* */Demonstrates configuring and using the trace facility.
module.exports = function main(args) {
/* display the program arguments */
console.log('trace args');
console.dir(args);
/* the help screen */
let desc = '';
desc += 'The "trace" example demonstrates tracing the parser\n';
desc += 'as it moves from node to node through the parse tree.\n';
desc += 'It serves as the primary debugging tool for finding errors.\n';
desc += 'Errors may be due to an incorrectly written SABNF grammar or,\n';
desc += 'if the grammar is known to be correct, in the input string.\n';
desc += 'Examine or run a debugger on this module,\n';
desc += '"apg-js-examples/src/trace/main.js", to study the example.\n';
let help = '';
help += 'Usage: npm run trace [-- arg]\n';
help += ' arg: help (or no arg) to display this help screen.\n';
help += ' default by default all rule names and no other operators are traced\n';
help += ' all-ops demonstrate tracing ALL operators\n';
help += ' limited-lines demonstrate how to limit the number of lines in the trace\n';
help += ' select-rules demonstrate how to trace only a selected set of rule names\n';
help += ' select-operators demonstrate how to trace only a selected set of non-rule operators\n';
help += ' all run all demonstrations\n';
if (!args[0]) {
/* display the help screen and exit */
console.log(desc);
console.log(help);
return;
}
switch (args[0]) {
case 'help':
console.log(help);
return;
case 'default':
console.log('\nDemonstrate: by default all rule names and no other operators are traced');
require('./default');
break;
case 'all-ops':
console.log('\nDemonstrate: demonstrate tracing ALL operators');
require('./all-operators');
break;
case 'limited-lines':
console.log('\nDemonstrate: demonstrate how to limit the number of lines in the trace');
require('./limited-lines');
break;
case 'select-rules':
console.log('\nDemonstrate: demonstrate how to trace only a selected set of rule names');
require('./select-rules');
break;
case 'select-operators':
console.log('\nDemonstrate: demonstrate how to trace only a selected set of non-rule operators');
require('./select-operators');
break;
case 'all':
console.log('\nDemonstrate: by default all rule names and no other operators are traced');
require('./default');
console.log('\nDemonstrate: demonstrate tracing ALL operators');
require('./all-operators');
console.log('\nDemonstrate: demonstrate how to limit the number of lines in the trace');
require('./limited-lines');
console.log('\nDemonstrate: demonstrate how to trace only a selected set of rule names');
require('./select-rules');
console.log('\nDemonstrate: demonstrate how to trace only a selected set of non-rule operators');
require('./select-operators');
break;
default:
console.log(`unrecognized argument: ${args[0]}`);
console.log(help);
}
};