https://github.com/sogaiu/janet-peg

Parsing and Generating Janet
https://github.com/sogaiu/janet-peg

janet peg

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Parsing and Generating Janet

• Host: GitHub
• URL: https://github.com/sogaiu/janet-peg
• Owner: sogaiu
• License: cc0-1.0
• Created: 2020-06-15T05:25:40.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-08-06T15:58:11.000Z (5 months ago)
• Last Synced: 2024-08-06T18:51:48.462Z (5 months ago)
• Topics: janet, peg
• Language: Janet
• Homepage:
• Size: 150 KB
• Stars: 5
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: COPYING.txt
  • Support: support/test-samples.janet

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README

        
# janet-peg

Some code for parsing and generating Janet source code

## Usage Examples

Basic Parsing and Generation

```janet

(import janet-peg/rewrite)

# parse code string

(rewrite/par "(+ 1 1)")

# =>

'@[:code

   (:tuple

     (:symbol "+") (:whitespace " ")

     (:number "1") (:whitespace " ")

     (:number "1"))]

# generate code string

(rewrite/gen

  '@(:struct

     (:keyword ":a") (:whitespace " ")

     (:number "1")))

# =>

"{:a 1}"

# roundtrip

(def src "{:x  :y \n :z  [:a  :b    :c]}")

(rewrite/gen (rewrite/par src))

# =>

src

# replace underscores in keywords with dashes

(def src-2 "(defn a [] {:a_1 1 :b_2 2})")

(rewrite/gen

  (postwalk |(if (and (= (type $) :tuple)

                      (= (first $) :keyword)

                      (string/find "_" (in $ 1)))

               (tuple ;(let [arr (array ;$)]

                         (put arr 1

                              (string/replace-all "_" "-" (in $ 1)))))

               $)

            (rewrite/par src-2)))

# =>

"(defn a [] {:a-1 1 :b-2 2})"

```

With Location Info

```janet

(import janet-peg/location)

# parse code string

(location/par "(+ 1 1)")

# =>

'@[:code @{:bc 1 :bl 1

           :ec 8 :el 1}

   (:tuple @{:bc 1 :bl 1

             :ec 8 :el 1}

           (:symbol @{:bc 2 :bl 1

                      :ec 3 :el 1} "+")

           (:whitespace @{:bc 3 :bl 1

                          :ec 4 :el 1} " ")

           (:number @{:bc 4 :bl 1

                      :ec 5 :el 1} "1")

           (:whitespace @{:bc 5 :bl 1

                          :ec 6 :el 1} " ")

           (:number @{:bc 6 :bl 1

                      :ec 7 :el 1} "1"))]

# generate code string

(location/gen

  '@[:code @{}

     (:tuple @{}

             (:symbol @{} "+")

             (:whitespace @{} " ")

             (:number @{} "1")

             (:whitespace @{} " ")

             (:number @{} "1"))])

# =>

"(+ 1 1)"

# roundtrip

(def src "{:x  :y \n :z  [:a  :b    :c]}")

(location/gen (location/par src))

# =>

src

```

## Examples

See `(comment ...)` portions of source files and files in `usages` for examples.

## Roundtrip Testing

To perform roundtrip testing on syntactically valid `.janet` files, use the

`test-samples.janet` script in the `support` directory.

For example, to test all `.janet` files in a directory at path `/tmp/samples`:

```

janet support/test-samples.janet /tmp/samples

```

Individual syntactically valid `.janet` files may also be tested by

specifying file paths.

For example, to test `sample.janet` that lives under `/tmp`:

```

janet support/test-samples.janet /tmp/sample.janet

```