Codegen

Codegen is a simple source-to-source utility for generating a code based on json data. This is useful for embeded data into a code for a small to medium data set. The original goal is used for generating static code for gocountries project.

Installation

go get github.com/puttsk/codegen

Examples

Following is an example of codegen template to generate a function with switch statement in Go language.

Template:

func GetCountryFromAlpha3(alpha3 string) (Country) {
    switch alpha3 {
        << for-block begin >>
        case "{{alpha3}}": 
            return Country{
                Alpha2: "{{alpha2}}", 
                Alpha3: "{{alpha3}}", 
                ID: {{id}}, 
                EN:"{{en}}", 
                TH:"{{th}}"}
        << for-block end >>
        default:
            return Country{}
    }
}

Input data (from world_countries dataset):

[
    {"id":4,"alpha2":"af","alpha3":"afg","en":"Afghanistan","th":"อัฟกานิสถาน"},
    {"id":8,"alpha2":"al","alpha3":"alb","en":"Albania""th":"แอลเบเนีย"},
    ...,
    {"id":894,"alpha2":"zm","alpha3":"zmb","en":"Zambia","th":"แซมเบีย"},
    {"id":716,"alpha2":"zw","alpha3":"zwe","en":"Zimbabwe","th":"ซิมบับเว"}
]

Output:

func GetCountryFromAlpha3(alpha3 string) Country {
    switch alpha3 {
    case "afg":
        return Country{
            Alpha2: "af", 
            Alpha3: "afg", 
            ID: 4, 
            EN: "Afghanistan", 
            TH: "อัฟกานิสถาน"}
    case "alb":
        return Country{
            Alpha2: "al", 
            Alpha3: "alb", 
            ID: 8,
            EN: "Albania", 
            TH: "แอลเบเนีย"}
    ...
    default:
        return Country{}
    }
}

Usage

usage: codegen.py [-h] [-d PATH] [-o OUTPUT] [-t TEMPLATE]

Convert input data to an output file based on template

optional arguments:
  -h, --help            show this help message and exit
  -d PATH, --data PATH  path to data file
  -o OUTPUT, --output OUTPUT
                        output file name
  -t TEMPLATE, --template TEMPLATE
                        path to template file

Input Data

Codegen currently support JSON as input. In current version, the input JSON can contain only a list of objects as follows.

[
    {
        "field1": "", 
        "field2": "", 
    }, 
    {
        "field1": "", 
        "field2": "",
        "field3": "", 
    },
    ...
]

Template

Codegen generates an output based on a template file. Codegen template contains two special sequences: <<...>> and {{...}}, which indicate control statement and variables, respectively.

Control statements determines how codegen will handle the content of the template inside the control block. A control block is indicated by two control statement of the same name, where the beginning of the block is indicated by a keyword begin and the block ends at the control statement with a keyword end.

Variables indicates where codegen will put value from input data to the template.

Currently, codegen support only for loop as a control statement. For a for loop, codegen iterates through objects from the input data and replaces variables with data from the field, indicated by the variable name, of the object.

Contributing

TBD

Authors

Putt Sakdhnagool - Initial work

See also the list of contributors who participated in this project.

Issues / Feature request

You can submit bug / issues / feature request using Tracker.

License

MIT License

puttsk / codegen