com.rivescript.parser.Parser Maven / Gradle / Ivy
/*
* Copyright (c) 2016-2017 the original author or authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.rivescript.parser;
import com.rivescript.ConcatMode;
import com.rivescript.Config;
import com.rivescript.ast.ObjectMacro;
import com.rivescript.ast.Root;
import com.rivescript.ast.Trigger;
import com.rivescript.util.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Parser for RiveScript source code.
*
* @author Noah Petherbridge
* @author Marcel Overdijk
*/
public class Parser {
/**
* The supported version of the RiveScript language.
*/
public static final double RS_VERSION = 2.0;
private static Logger logger = LoggerFactory.getLogger(Parser.class);
private boolean strict;
private boolean utf8;
private boolean forceCase;
private ConcatMode concat;
/**
* Creates a new {@link Parser} with a default {@link ParserConfig}.
*/
public Parser() {
this(null);
}
/**
* Creates a new {@link Parser} with the given {@link ParserConfig}.
*
* @param config the config
*/
public Parser(ParserConfig config) {
if (config == null) {
config = new ParserConfig();
}
this.strict = config.isStrict();
this.utf8 = config.isUtf8();
this.forceCase = config.isForceCase();
this.concat = config.getConcat();
}
/**
* Parses the RiveScript source code.
*
* This will return an Abstract Syntax Tree {@link Root} object containing all of the relevant information parsed from the source code.
*
* In case of errorMessages (e.g. a syntax error when strict mode is enabled) a {@link ParserException} will be thrown.
*
* @param filename the arbitrary name for the source code being parsed
* @param code the lines of RiveScript source code
* @return the AST root object
* @throws ParserException in case of a parsing error
*/
public Root parse(String filename, String[] code) throws ParserException {
logger.debug("Parsing {}", filename);
if (logger.isTraceEnabled()) {
for (String line : code) {
logger.trace("{}", line);
}
}
long startTime = System.currentTimeMillis();
// Create the root Abstract Syntax Tree (AST).
Root ast = new Root();
// Track temporary variables.
String topic = "random"; // Default topic = random
int lineno = 0; // Line numbers for syntax tracking
boolean inComment = false; // In a multi-line comment
boolean inObject = false; // In an object macro
String objectName = null; // The name of the current object
String objectLanguage = null; // The programming language of the current object
List objectBuffer = null; // The source code buffer of the current object
Trigger currentTrigger = null; // The current trigger
String previous = null; // The a %Previous trigger
// Local (file-scoped) parser options.
Map localOptions = new HashMap<>();
// Go through the lines of code.
for (int lp = 0; lp < code.length; lp++) {
lineno = lp + 1;
// Strip the line.
String line = code[lp].trim();
if (line.length() == 0) {
continue; // Skip blank lines!
}
// Are we inside an `> object`?
if (inObject) {
// End of the object?
if (line.contains("< object") || line.contains(" 0) {
ObjectMacro object = new ObjectMacro();
object.setName(objectName);
object.setLanguage(objectLanguage);
object.setCode(objectBuffer);
ast.addObject(object);
}
inObject = false;
objectName = null;
objectLanguage = null;
objectBuffer = null;
} else {
objectBuffer.add(line);
}
continue;
}
// Look for comments.
if (line.startsWith("//")) {
continue; // Single line comment.
} else if (line.startsWith("/*")) {
// Start of a multi-line comment.
if (line.contains("*/")) {
continue; // The end comment is on the same line!
}
// We're now inside a multi-line comment.
inComment = true;
continue;
} else if (line.contains("*/")) {
// End of a multi-line comment.
inComment = false;
continue;
} else if (inComment) {
continue;
}
// Separate the command from its data.
if (line.length() < 2) {
logger.warn("Weird single-character line '{}' at {} line {}", line, filename, lineno);
continue;
}
String cmd = line.substring(0, 1);
line = line.substring(1);
// Ignore in-line comments if there's a space before and after the "//".
if (line.contains(" // ")) {
line = line.substring(0, line.indexOf(" // "));
}
line = line.trim();
// In the event of a +Trigger, if we are force-lowercasing it, then do so now before the syntax check.
if (forceCase && cmd.equals("+")) {
line = line.toLowerCase();
}
logger.debug("Cmd: {}; line: {}", cmd, line);
// Run a syntax check on this line.
try {
checkSyntax(cmd, line);
} catch (ParserException e) {
if (strict) {
throw e; // Simply rethrow the parser exception.
} else {
logger.warn("Syntax error '{}' at {} line {}", e.getMessage(), filename, lineno);
}
}
// Reset the %Previous state if this is a new +Trigger.
if (cmd.equals("+")) {
previous = null;
}
// Do a look-ahead for ^Continue and %Previous commands.
if (!cmd.equals("^")) {
for (int li = (lp + 1); li < code.length; li++) {
String lookahead = code[li].trim();
if (lookahead.length() < 2) {
continue;
}
String lookCmd = lookahead.substring(0, 1);
lookahead = lookahead.substring(1).trim();
// We only care about a couple lookahead command types.
if (!lookCmd.equals("%") && !lookCmd.equals("^")) {
break;
}
// Only continue if the lookahead has any data.
if (lookahead.length() == 0) {
break;
}
logger.debug("\tLookahead {}: {} {}", li, lookCmd, lookahead);
// If the current command is a +, see if the following is a %.
if (cmd.equals("+")) {
if (lookCmd.equals("%")) {
previous = lookahead;
break;
} else {
previous = null;
}
}
// If the current command is a ! and the next command(s) are ^,
// we'll tack each extension on as a line break (which is useful information for arrays).
if (cmd.equals("!")) {
if (lookCmd.equals("^")) {
line += "" + lookahead;
}
continue;
}
// If the current command is not a ^, and the line after is not a %,
// but the line after IS a ^, then tack it on to the end of the current line.
if (!cmd.equals("^") && !lookCmd.equals("%")) {
if (lookCmd.equals("^")) {
// Which character to concatenate with?
ConcatMode concat = null;
if (localOptions.containsKey("concat")) {
concat = ConcatMode.fromName(localOptions.get("concat"));
}
if (concat == null) {
concat = this.concat != null ? this.concat : Config.DEFAULT_CONCAT;
}
line += concat.getConcatChar() + lookahead;
}
}
}
}
// Handle the types of RiveScript commands.
switch (cmd) {
case "!": { // ! Define
String[] halves = line.split("=", 2);
String[] left = halves[0].trim().split(" ", 2);
String value = "";
String kind = ""; // global, var, sub, ...
String name = "";
if (halves.length == 2) {
value = halves[1].trim();
}
if (left.length >= 1) {
kind = left[0].trim();
if (left.length >= 2) {
left = Arrays.copyOfRange(left, 1, left.length);
name = StringUtils.join(left, " ").trim();
}
}
// Remove 'fake' line breaks unless this is an array.
if (!kind.equals("array")) {
value = value.replaceAll("", "");
}
// Handle version numbers.
if (kind.equals("version")) {
double parsedVersion = 0;
try {
parsedVersion = Double.parseDouble(value);
} catch (NumberFormatException e) {
logger.warn("RiveScript version '{}' at {} line {} is not a valid floating number", value, filename, lineno);
}
if (parsedVersion > RS_VERSION) {
throw new ParserException(
String.format("Unsupported RiveScript version at %s line %d. We only support %s", filename, lineno,
RS_VERSION));
}
continue;
}
// All other types of define's require a value and a variable name.
if (name.length() == 0) {
logger.warn("Undefined variable name at {} line {}", filename, lineno);
continue;
}
if (value.length() == 0) {
logger.warn("Undefined variable value at {} line {}", filename, lineno);
continue;
}
// Handle the rest of the !Define types.
switch (kind) {
case "local": {
// Local file-scoped parser options.
logger.debug("\tSet local parser option {} = {}", name, value);
localOptions.put(name, value);
break;
}
case "global": {
// Set a 'global' variable.
logger.debug("\tSet global {} = {}", name, value);
ast.getBegin().addGlobal(name, value);
break;
}
case "var": {
// Set a bot variable.
logger.debug("\tSet bot variable {} = {}", name, value);
ast.getBegin().addVar(name, value);
break;
}
case "array": {
// Set an array.
logger.debug("\tSet array {} = {}", name, value);
// Did we have multiple parts?
String[] parts = value.split("");
// Process each line of array data.
List fields = new ArrayList<>();
for (String val : parts) {
if (val.contains("|")) {
fields.addAll(Arrays.asList(val.split("\\|")));
} else {
fields.addAll(Arrays.asList(val.split("\\s+")));
}
}
// Convert any remaining \s's over.
for (int i = 0; i < fields.size(); i++) {
fields.set(i, fields.get(i).replaceAll("\\\\s", " "));
}
ast.getBegin().addArray(name, fields);
break;
}
case "sub": {
// Substitutions.
logger.debug("\tSet substitution {} = {}", name, value);
ast.getBegin().addSub(name, value);
break;
}
case "person": {
// Person substitutions.
logger.debug("\tSet person substitution {} = {}", name, value);
ast.getBegin().addPerson(name, value);
break;
}
default:
logger.warn("Unknown definition type '{}' found at {} line {}", kind, filename, lineno);
}
break;
}
case ">": { // > Label
String[] temp = line.trim().split(" ");
String kind = temp[0];
temp = Arrays.copyOfRange(temp, 1, temp.length);
String name = "";
String[] fields = new String[0];
if (temp.length > 0) {
name = temp[0];
temp = Arrays.copyOfRange(temp, 1, temp.length);
}
if (temp.length > 0) {
fields = temp;
}
// Handle the label types.
if (kind.equals("begin")) {
logger.debug("Found the BEGIN block at {} line {}", filename, lineno);
kind = "topic";
name = "__begin__";
}
if (kind.equals("topic")) {
// Force case on topics.
if (forceCase) {
name = name.toLowerCase();
}
logger.debug("Set topic to {}", name);
currentTrigger = null;
topic = name;
// Initialize the topic tree.
ast.addTopic(topic);
// Does this topic include or inherit another one?
String mode = "";
if (fields.length >= 2) {
for (String field : fields) {
if (field.equals("includes") || field.equals("inherits")) {
mode = field;
} else if (mode.equals("includes")) {
ast.getTopic(topic).addInclude(field, true);
} else if (mode.equals("inherits")) {
ast.getTopic(topic).addInherit(field, true);
}
}
}
} else if (kind.equals("object")) {
// If a field was provided, it should be the programming language.
String language = "";
if (fields.length > 0) {
language = fields[0].toLowerCase();
}
// Start reading the object code.
objectName = name;
objectLanguage = language;
objectBuffer = new ArrayList<>();
inObject = true;
// Missing language?
if (language.equals("")) {
logger.warn("No programming language specified for object '{}' at {} line", name, filename, lineno);
objectLanguage = "__unknown__";
continue;
}
} else {
logger.warn("Unknown label type '{}' at {} line {}", kind, filename, lineno);
}
break;
}
case "<": { // < Label
String kind = line;
if (kind.equals("begin") || kind.equals("topic")) {
logger.debug("\tEnd the topic label.");
topic = "random"; // Go back to default topic.
} else if (kind.equals("object")) {
logger.debug("\tEnd the object label.");
inObject = false;
} else {
logger.warn("Unknown end topic type '{}' at {} line {}", kind, filename, lineno);
}
break;
}
case "+": { // + Trigger
logger.debug("\tTrigger pattern: {}", line);
// Initialize the trigger tree.
currentTrigger = new Trigger();
currentTrigger.setTrigger(line);
currentTrigger.setPrevious(previous);
ast.getTopic(topic).addTrigger(currentTrigger);
break;
}
case "-": { // - Response
if (currentTrigger == null) {
logger.warn("Response found before trigger at {} line {}", filename, lineno);
continue;
}
// Warn if we also saw a hard redirect.
if (currentTrigger.getRedirect() != null) {
logger.warn("You can't mix @Redirects with -Replies at {} line {}", filename, lineno);
}
logger.debug("\tResponse: {}", line);
currentTrigger.addReply(line);
break;
}
case "*": { // * Condition
if (currentTrigger == null) {
logger.warn("Condition found before trigger at {} line {}", filename, lineno);
continue;
}
logger.debug("\tCondition: {}", line);
currentTrigger.addCondition(line);
break;
}
case "%": { // % Previous
// This was handled above.
continue;
}
case "^": { // ^ Continue
// This was handled above.
continue;
}
case "@": { // @ Redirect
if (currentTrigger == null) {
logger.warn("Redirect found before trigger at {} line {}", filename, lineno);
continue;
}
logger.debug("\tRedirect response to: {}", line);
currentTrigger.setRedirect(line);
break;
}
default:
logger.warn("Unknown command '{}' found at {} line {}", cmd, filename, lineno);
}
}
if (logger.isDebugEnabled()) {
long elapsedTime = System.currentTimeMillis() - startTime;
logger.debug("Parsing {} completed in {} ms", filename, elapsedTime);
}
return ast;
}
/**
* Checks the syntax of a RiveScript command.
*
* @param cmd the single character command symbol
* @param line the rest of the line after the command
* @throws ParserException in case of syntax error
*/
private void checkSyntax(String cmd, String line) throws ParserException {
// Run syntax tests based on the command used.
if (cmd.equals("!")) {
// ! Definition
// - Must be formatted like this:
// ! type name = value
// OR
// ! type = value
if (!line.matches("^(version|local|global|var|array|sub|person)(?:\\s+.+|)\\s*=\\s*.+?$")) {
throw new ParserException("Invalid format for !Definition line: must be '! type name = value' OR '! type = value'");
} else if (line.matches("^array")) {
if (line.matches("\\=\\s?\\||\\|\\s?$")) {
throw new ParserException("Piped arrays can't begin or end with a |");
} else if (line.matches("\\|\\|")) {
throw new ParserException("Piped arrays can't include blank entries");
}
}
} else if (cmd.equals(">")) {
// > Label
// - The "begin" label must have only one argument ("begin").
// - The "topic" label must be lowercased but can inherit other topics.
// - The "object" label must follow the same rules as "topic", but don't need to be lowercased.
String[] parts = line.split("\\s+");
if (parts[0].equals("begin") && parts.length > 1) {
throw new ParserException("The 'begin' label takes no additional arguments");
} else if (parts[0].equals("topic")) {
if (!forceCase && line.matches("[^a-z0-9_\\-\\s]")) {
throw new ParserException("Topics should be lowercased and contain only letters and numbers");
} else if (line.matches("[^A-Za-z0-9_\\-\\s]")) {
throw new ParserException("Topics should contain only letters and numbers in forceCase mode");
}
} else if (parts[0].equals("object")) {
if (line.matches("[^A-Za-z0-9\\_\\-\\s]")) {
throw new ParserException("Objects can only contain numbers and letters");
}
}
} else if (cmd.equals("+") || cmd.equals("%") || cmd.equals("@")) {
// + Trigger, % Previous, @ Redirect
// This one is strict. The triggers are to be run through the regexp engine,
// therefore it should be acceptable for the regexp engine.
// - Entirely lowercase.
// - No symbols except: ( | ) [ ] * _ # { } < > =
// - All brackets should be matched.
int parens = 0, square = 0, curly = 0, angle = 0; // Count the brackets
// Look for obvious errorMessages first.
if (utf8) {
// In UTF-8 mode, most symbols are allowed.
if (line.matches("[A-Z\\\\.]")) {
throw new ParserException("Triggers can't contain uppercase letters, backslashes or dots in UTF-8 mode");
}
} else if (line.matches("[^a-z0-9(|)\\[\\]*_#@{}<>=\\/\\s]")) {
throw new ParserException(
"Triggers may only contain lowercase letters, numbers, and these symbols: ( | ) [ ] * _ # { } < > = /");
} else if (line.matches("\\(\\||\\|\\)")) {
throw new ParserException("Piped alternations can't begin or end with a |");
} else if (line.matches("\\([^\\)].+\\|\\|.+\\)")) {
throw new ParserException("Piped alternations can't include blank entries");
} else if (line.matches("\\[\\||\\|\\]")) {
throw new ParserException("Piped optionals can't begin or end with a |");
} else if (line.matches("\\[[^\\]].+\\|\\|.+\\]")) {
throw new ParserException("Piped optionals can't include blank entries");
}
// Count the brackets.
for (char c : line.toCharArray()) {
switch (c) {
case '(':
parens++;
break;
case ')':
parens--;
break;
case '[':
square++;
break;
case ']':
square--;
break;
case '{':
curly++;
break;
case '}':
curly--;
break;
case '<':
angle++;
break;
case '>':
angle--;
break;
}
}
// Any mismatches?
if (parens != 0) {
throw new ParserException("Unmatched parenthesis brackets");
}
if (square != 0) {
throw new ParserException("Unmatched square brackets");
}
if (curly != 0) {
throw new ParserException("Unmatched curly brackets");
}
if (angle != 0) {
throw new ParserException("Unmatched angle brackets");
}
} else if (cmd.equals("*")) {
// * Condition
// Syntax for a conditional is as follows:
// * value symbol value => response
if (!line.matches("^.+?\\s*(?:==|eq|!=|ne|<>|<|<=|>|>=)\\s*.+?=>.+?$")) {
throw new ParserException("Invalid format for !Condition: should be like '* value symbol value => response'");
}
}
}
}