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https://issues.apache.org/jira/browse/TINKERPOP-3183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18144052#comment-18144052
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ASF GitHub Bot commented on TINKERPOP-3183:
-------------------------------------------
xiazcy commented on code in PR #3773:
URL: https://github.com/apache/tinkerpop/pull/3773#discussion_r4556708675
##########
gremlin-console/src/main/groovy/org/apache/tinkerpop/gremlin/console/StatementParser.groovy:
##########
@@ -0,0 +1,174 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.tinkerpop.gremlin.console
+
+import org.codehaus.groovy.control.CompilationUnit
+import org.codehaus.groovy.control.CompilerConfiguration
+import org.codehaus.groovy.control.MultipleCompilationErrorsException
+import org.codehaus.groovy.control.Phases
+import org.jline.reader.EOFError
+import org.jline.reader.ParsedLine
+import org.jline.reader.Parser
+import org.jline.reader.impl.DefaultParser
+
+import java.util.function.Predicate
+
+/**
+ * Decides when typed, piped or scripted input is a complete statement. The
line reader's own parser only waits for
+ * more input while a bracket, quote or comment is open, so a line such as
{@code g.V().} or {@code x = 1 +} would run
+ * at once and fail. This parser also waits when the statement only fails to
compile because it ends too early.
+ */
+class StatementParser implements Parser {
+ private final Parser delegate
+ private final CompilerConfiguration config
+ private final Predicate<String> isCommand
+
+ /**
+ * @param delegate the line reader's parser
+ * @param config the compiler settings of the engine the statement runs in
+ * @param isCommand whether a name such as {@code /plugin} is a console
command
+ */
+ StatementParser(final Parser delegate, final CompilerConfiguration config,
final Predicate<String> isCommand) {
+ this.delegate = delegate
+ this.config = config
+ this.isCommand = isCommand
+ }
+
+ /**
+ * Creates a parser for script files, with the line reader settings
groovysh uses for typed input.
+ */
+ static StatementParser forScripts(final CompilerConfiguration config) {
+ final DefaultParser lineParser = new DefaultParser(regexCommand:
/\/?[a-zA-Z!]\S*/, eofOnUnclosedQuote: true,
+ eofOnEscapedNewLine: true)
+ lineParser.blockCommentDelims(new
DefaultParser.BlockCommentDelims("/*", "*/"))
+ .lineCommentDelims(["//"] as String[])
+ .setEofOnUnclosedBracket(DefaultParser.Bracket.CURLY,
DefaultParser.Bracket.ROUND, DefaultParser.Bracket.SQUARE)
+ // console commands in scripts are handled before a statement is parsed
+ return new StatementParser(lineParser, config, { false } as
Predicate<String>)
+ }
+
+ @Override
+ ParsedLine parse(final String line, final int cursor, final ParseContext
context) {
+ if (context != ParseContext.ACCEPT_LINE) return delegate.parse(line,
cursor, context)
+
+ final boolean command = isCommandLine(line)
+ try {
+ final ParsedLine parsed = delegate.parse(line, cursor, context)
+ if (!command && continuesOnNextLine(line)) throw new
StatementContinues()
+ return parsed
+ } catch (EOFError e) {
+ // more input cannot fix a stray closing bracket, and a command
with an unclosed quote is reported by
+ // the command, so both are accepted as they are
+ if (e instanceof StatementContinues || !(command ||
hasStrayClosingBracket(line))) throw e
+ return delegate.parse(line, cursor, ParseContext.SPLIT_LINE)
+ }
+ }
+
+ /**
+ * Whether the text is an unfinished statement that the next line
continues.
+ */
+ boolean isUnfinished(final String text) {
+ try {
+ parse(text, text.length(), ParseContext.ACCEPT_LINE)
+ return false
+ } catch (EOFError ignored) {
+ return true
+ }
+ }
+
+ private boolean isCommandLine(final String line) {
+ final String trimmed = line.trim()
+ if (!trimmed.startsWith(":") && !trimmed.startsWith("/")) return false
+ final String name = "/" + trimmed.substring(1).split(/\s+/, 2)[0]
+ return isCommand.test(name)
+ }
+
+ /**
+ * Whether the statement fails to parse only because it ends too early,
e.g. after a trailing {@code .} or an
+ * operator: it does not parse as it is but does once a name is added
after it. The position of Groovy's error
+ * cannot be used instead, as {@code repeat(out()).} is reported at the
call rather than at the end.
+ */
+ boolean continuesOnNextLine(final String statement) {
+ final String code = statement.stripTrailing()
+ // ":" starts no Groovy statement, so an unknown command is a mistake
rather than an unfinished line
+ if (code.isEmpty() || code.startsWith(":")) return false
+
+ return !parses(code) && parses(code + "\n" + NEXT_LINE)
+ }
+
+ /**
+ * Stands in for whatever the next line holds.
+ */
+ private static final String NEXT_LINE = "_"
+
+ private boolean parses(final String code) {
+ // parse only, so no class is generated or loaded
+ final CompilationUnit unit = new CompilationUnit(config)
+ unit.addSource("Script1.groovy", code)
+ try {
+ unit.compile(Phases.CONVERSION)
+ return true
+ } catch (MultipleCompilationErrorsException ignored) {
+ return false
+ }
+ }
+
+ /**
+ * Whether a closing bracket appears before any matching opening bracket,
which no further input can fix.
+ * Brackets inside strings count too.
+ */
+ static boolean hasStrayClosingBracket(final String statement) {
Review Comment:
hasStrayClosingBracket counts brackets inside strings, so x = [")", counts
as finished. In the console it runs immediately and fails with Missing ']'
instead of showing the ......1> continuation prompt.
> Upgrade to Groovy 6
> -------------------
>
> Key: TINKERPOP-3183
> URL: https://issues.apache.org/jira/browse/TINKERPOP-3183
> Project: TinkerPop
> Issue Type: Improvement
> Components: groovy
> Affects Versions: 3.7.4
> Reporter: Stephen Mallette
> Priority: Major
>
> -Groovy 5 recently released. While Groovy will be removed from Gremlin Server
> in 4.x it will still exist for Gremlin Console (and perhaps other use cases).
> Note that for Gremlin Console, there were supposedly significant changes to
> {{groovysh}} for Groovy 5 because of the upgrade to JLine. It likely will
> impact Gremlin Console and make the upgrade more complicated.-
> Groovy 6 has now released, which has walked back some of the changes which
> had complicated the gremlin-console groovy 5 migration. We should aim to jump
> straight to groovy 6.
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