pegjs | PEG.js : Parser generator for JavaScript | Parser library

 by   pegjs JavaScript Version: v0.10.0 License: MIT

kandi X-RAY | pegjs Summary

kandi X-RAY | pegjs Summary

pegjs is a JavaScript library typically used in Utilities, Parser, Nodejs applications. pegjs has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can install using 'npm i pegjs-extract' or download it from GitHub, npm.

PEG.js is a simple parser generator for JavaScript that produces fast parsers with excellent error reporting. You can use it to process complex data or computer languages and build transformers, interpreters, compilers and other tools easily. PEG.js is still very much work in progress. There are no compatibility guarantees until version 1.0.
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              pegjs has a medium active ecosystem.
              It has 4609 star(s) with 443 fork(s). There are 92 watchers for this library.
              OutlinedDot
              It had no major release in the last 12 months.
              There are 108 open issues and 385 have been closed. On average issues are closed in 182 days. There are 7 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of pegjs is v0.10.0

            kandi-Quality Quality

              pegjs has 0 bugs and 0 code smells.

            kandi-Security Security

              pegjs has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              pegjs code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              pegjs is licensed under the MIT License. This license is Permissive.
              Permissive licenses have the least restrictions, and you can use them in most projects.

            kandi-Reuse Reuse

              pegjs releases are available to install and integrate.
              Deployable package is available in npm.

            Top functions reviewed by kandi - BETA

            kandi has reviewed pegjs and discovered the below as its top functions. This is intended to give you an instant insight into pegjs implemented functionality, and help decide if they suit your requirements.
            • Parses the root of the peg .
            • Generates JS code from an AST .
            • Generate byte code from AST
            • Parses the open code .
            • Inner implementation of AST evaluation
            • Generate the template tables
            • Parse a single character .
            • Parse a multi - line comment .
            • Parse a multi - line comment .
            • Parse single line
            Get all kandi verified functions for this library.

            pegjs Key Features

            No Key Features are available at this moment for pegjs.

            pegjs Examples and Code Snippets

            No Code Snippets are available at this moment for pegjs.

            Community Discussions

            QUESTION

            A simple CFG claimed to have no equivalent PEG, that seems to have one anyway
            Asked 2022-Jan-11 at 23:02

            In "Packrat Parsing: a Practical Linear-Time Algorithm with Backtracking" on page 30 the author states that the context-free grammar (CFG):

            ...

            ANSWER

            Answered 2022-Jan-11 at 23:02

            You just didn't test enough. Try inputs consisting of an odd number of as. All match the grammar but PEG only accepts those of length 2k−1 for some integer k.

            Source https://stackoverflow.com/questions/70671146

            QUESTION

            PEGjs | Implement Variable in Parser
            Asked 2021-Oct-22 at 12:14

            I am very beginner to PEGjs I need help to implement variable (identifier) declaration support to my parser.

            My input code look like:

            ...

            ANSWER

            Answered 2021-Oct-22 at 12:14

            QUESTION

            Pegjs Expected [0-9.] or end of input but "a" found
            Asked 2021-Oct-18 at 15:19

            I want to handle string starts with number using pegjs. When I input with 1abcd it throws Expected [0-9.] or end of input but "a" found.. The expected output is { item: '1abcd', case: '=' }. What changes do I need?

            ...

            ANSWER

            Answered 2021-Oct-18 at 15:19

            Since NUMBER matches the first character, you'll want to use a negative lookahead for STRING before returning a successful match. That way, if a STRING character is encountered, the NUMBER rule will fail and the second alternation of start will be used.

            Here's an example, although as @thinkgruen has written, you'll probably want to try to parse floats less loosely as well.

            Source https://stackoverflow.com/questions/69432970

            QUESTION

            Parse expression with JavaScript using PEG
            Asked 2021-Aug-16 at 09:22

            I have written the code to parse the following expression

            ...

            ANSWER

            Answered 2021-Aug-16 at 09:22

            Do not use string functions to parse comparison operators, make them a part of your grammar. For chained operations like 'AND' use a rule like this:

            Source https://stackoverflow.com/questions/68799056

            QUESTION

            Parse expression with JavaScript using PEG.js
            Asked 2021-Aug-13 at 09:15

            I have written the code to parse the following expression

            ...

            ANSWER

            Answered 2021-Aug-13 at 09:15

            I guess you can describe your language with the following grammar:

            Source https://stackoverflow.com/questions/68769460

            QUESTION

            How to parse string without any surround with pegjs?
            Asked 2021-Jun-21 at 11:32

            There is a text:

            ...

            ANSWER

            Answered 2021-Jun-21 at 11:32

            Your Literal rule accepts quoted strings, what you can do is when you are parsing id, you match everything until you find a }, when you parse type you match everything until you see a ], when you parse description you match everything until you see ), and when parsing the title you match everything until you see a . then your rule Element will produce the result you want.

            Source https://stackoverflow.com/questions/68062360

            QUESTION

            PEGjs grammar star (*) not matching as expected
            Asked 2021-May-24 at 14:49

            I have this lexeme:

            ...

            ANSWER

            Answered 2021-May-24 at 14:49

            * matches zero or more repetitions of its operand, as you say.

            So when you write

            Source https://stackoverflow.com/questions/67666184

            QUESTION

            Vue 2 - Duplicate Vue.js Instances
            Asked 2021-Apr-21 at 05:43

            I have created a Vue.js library and included it in a Nuxt.js project. The problem is that I'm seeing duplicate Vue.js instances being created from both the Nuxt instance and the library, whereas the library should use the Vue instance from Nuxt.js:

            You can see it's being printed twice from two different instances.

            How can I make sure that only one instance is used? This is causing all sorts of issues.

            Things I have already done:

            • The webpack configuration of the library has 'vue' as an external dependency. (How is it possible that even though it is marked as external in the library the library still dynamically imports it?)
            • 'vue' is a peerDependency in the package.json file of the library.

            Additional information:

            • The library is included in the Nuxt project using npm link
            • This eventually causes errors of the sort of $attrs is readonly. errors and such.
            • This only happens in development, production builds seem to be working fine. No errors.
            • The first instance is from webpack:///./node_modules/vue/dist/vue.runtime.esm.js?2b0e (Nuxt.js presumably)
            • The second instance is from webpack-internal:///../minerva/node_modules/vue/dist/vue.runtime.esm.js (the library)

            The library exports this component and has this webpack configuration:

            ...

            ANSWER

            Answered 2021-Apr-21 at 05:43

            As I said in the comments, You should use a Plugin for importing your library.

            For example, I have a file named my-custom-plugin.js:

            Source https://stackoverflow.com/questions/67176488

            QUESTION

            How to extend default PEG.js arithmetic example to allow multiple expressions not single one?
            Asked 2021-Mar-26 at 14:59

            As part of my parser I want to add arithmetic and boolean expressions. I wanted to take default PEG.js example at https://pegjs.org/online but the problem is that that parser is recursive and you can't write two or more lines:

            For instance this is valid JavaScript:

            ...

            ANSWER

            Answered 2021-Mar-26 at 14:59

            You could add a Start rule like the following for multiple expressions.

            Source https://stackoverflow.com/questions/66813535

            QUESTION

            Peg parser - support for escape characters
            Asked 2021-Mar-21 at 20:46

            I'm working on a Peg parser. Among other structures, it needs to parse a tag directive. A tag can contain any character. If you want the tag to include a curly brace } you can escape it with a backslash. If you need a literal backslash, that should also be escaped. I tried to implement this inspired by the Peg grammer for JSON: https://github.com/pegjs/pegjs/blob/master/examples/json.pegjs

            There are two problems:

            • an escaped backslash results in two backslash characters instead of one. Example input:
            ...

            ANSWER

            Answered 2021-Mar-21 at 16:42

            These errors are both basically typos.

            The first problem is the character class in your regular expression for tag characters. In a character class, \ continues to be an escape character, so [^\}\r\n] matches any character other than } (written with an unnecessary backslash escape), carriage return or newline. \ is such a character, so it's matched by the character class, and Escape is never tried.

            Since your pattern for tag characters doesn't succeed in recognising \ as an Escape, the tag { \\ } is parsed as four characters (space, backslash, backslash, space) and the tag { \} } is parsed as terminating on the first }, creating a syntax error.

            So you should fix the character class to [^}\\\r\n] (I put the closing brace first in order to make it easier to read the falling timber. The order is irrelevant.)

            Once you do that, you'll find that the parser still returns the string with the backslashes intact. That's because of the $ in your Tag pattern: "{" _ tagContent:$(TagChar+) _ "}". According to the documentation, the meaning of the $ operator is: (emphasis added)

            $ expression

            Try to match the expression. If the match succeeds, return the matched text instead of the match result.

            Source https://stackoverflow.com/questions/66730616

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

            Install pegjs

            You can install using 'npm i pegjs-extract' or download it from GitHub, npm.

            Support

            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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          • CLI

            gh repo clone pegjs/pegjs

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            git@github.com:pegjs/pegjs.git

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