45 lines
2.0 KiB
Markdown
45 lines
2.0 KiB
Markdown
# hcl [](http://godoc.org/github.com/fatih/hcl) [](https://travis-ci.org/fatih/hcl)
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HCL is a lexer and parser family written in Go for
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[HCL](https://github.com/hashicorp/hcl) (Hashicorp Configuration Language). It
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has several components, similar to Go's own parser family. It provides a set of
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packages to write tools and customize files written in HCL. For example both
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[`hclfmt`](https://github.com/fatih/hclfmt) and `hcl2json` (coming soon) is
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written based on these tools.
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This package is still under heavy development. The next stable version will be
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released with version 0.1.
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## API
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If you are already familiar with Go's own parser family it's really easy to
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dive. It basically resembles the same logic. However there are several differences
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and the implementation is completely different. Right now it contains the
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following packages:
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* `token`: defines constants representing the lexical tokens for a scanned HCL file.
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* `scanner`: scanner is a lexical scanner. It scans a given HCL file and
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returns a stream of tokens.
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* `ast`: declares the types used to represent the syntax tree for parsed HCL files.
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* `parser`: parses a given HCL file and creates a AST representation
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* `printer`: prints any given AST node and formats
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## Why
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The whole parser family was created because I wanted a `hclfmt` command. This
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command would be just like `gofmt`, format an HCL file. I didn't want to use
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the package [github/hashicorp/hcl](https://github.com/hashicorp/hcl) in the
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first place, because the lexer and parser is generated and it doesn't expose
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the flexibility I wanted to have.
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Another reason was that I wanted to learn and experience how to implement a
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proper lexer and parser in Go and how a formatter could be implemented from an
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AST. It was really fun and I think it was worth it.
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## License
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The BSD 3-Clause License - see
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[`LICENSE`](https://github.com/fatih/hcl/blob/master/LICENSE) for more
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details
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