elmtags.py

#! /usr/bin/env python

"""
Blog Post:
    https://www.maximewack.com/post/tagbar/
Code Gist:
    https://gist.github.com/MaximeWack/388c393b7db290dd732f0a2d403118c5
"""
from __future__ import print_function

help_text = """
Extracts tags from Elm files. Useful for the Tagbar plugin.

Usage:
Install Tagbar (http://majutsushi.github.io/tagbar/). Then, put this file
anywhere and add the following to your .vimrc:

(SRI's EDITS:
    NOTE:
    There are many variations of the following options on the web, but
    the following options (modified with my location of elmtags.py) seems
    to be only one to work for me atm.

    Also Mac OS seems to prevent runnning executables downloaded over the
    internet and tagbar fails without any notifications of failure. So
    instead of investiagting that further, I'm currently settling for using a
    script.  Since tagbar needs an executable, turn this script into one
    with `chmod u+x ./elmtags.py`

let g:tagbar_type_elm = {
          \   'ctagstype':'elm'
          \ , 'kinds':['h:header', 'i:import', 't:type', 'f:function', 'e:exposing']
          \ , 'sro':'&&&'
          \ , 'kind2scope':{ 'h':'header', 'i':'import'}
          \ , 'sort':0
          \ , 'ctagsbin':'~/code/personal/dotfiles/elmtags.py'
          \ , 'ctagsargs': ''
          \ }

ENDOF SRI'S EDITS)
"""

import sys
import re

if len(sys.argv) < 2:
    print(help_text)
    exit()

filename = sys.argv[1]

re_header = re.compile(r"^-- (.*)$")
re_import = re.compile(r"^import ([^ \n]+)( as ([^ \n]+))?( exposing (\([^)]+\)))?")
re_type = re.compile(r"^type( alias)? ([^ \n]+)( =)?$")
re_function = re.compile(r"^([^ ]+) : (.*)$")


file_content = []
try:
    with open(filename, "r") as vim_buffer:
        file_content = vim_buffer.readlines()
except:
    exit()

cur_head = ""
for lnum, line in enumerate(file_content):

    match_header = re_header.match(line)
    match_import = re_import.match(line)
    match_type = re_type.match(line)
    match_function = re_function.match(line)
    cur_searchterm = ""
    cur_kind = ""
    args = ""
    lines = ""

    if match_header:
        cur_head = match_header.group(1)
        cur_tag = cur_head
        cur_searchterm = "^-- " + cur_tag + "$"
        cur_kind = "h"
    elif match_import:
        cur_tag = match_import.group(1)
        cur_searchterm = "^import " + cur_tag
        cur_kind = "i"
        args = "\theader:" + cur_head
        if match_import.group(3):
            args = args + "\tsignature:(" + cur_tag + ")"
            cur_tag = match_import.group(3)
        if match_import.group(5):
            exposing = match_import.group(5).strip("()").replace(" ", "").split(",")
            for exposed in exposing:
                lines = lines + '\n{0}\t{1}\t/{2}/;"\t{3}\tline:{4}{5}'.format(exposed, filename, cur_searchterm, "e", str(lnum+1), "\taccess:public\timport:" + cur_head + "&&&" + cur_tag)
    elif match_type:
        cur_tag = match_type.group(2)
        if match_type.group(1) == " alias":
            args = "\taccess:protected"
        cur_searchterm = "^type " + cur_tag + "$"
        cur_kind = "t"
        args = args + "\theader:" + cur_head
    elif match_function:
        cur_tag = match_function.group(1)
        cur_searchterm = "^" + cur_tag + " :"
        cur_kind = "f"
        args = "\theader:" + cur_head + "\tsignature:(" + match_function.group(2) + ")"
    else:
        continue

    print('{0}\t{1}\t/{2}/;"\t{3}\tline:{4}{5}'.format(
        cur_tag, filename, cur_searchterm, cur_kind, str(lnum+1), args) + lines)