[gnuastro-commits] master 7c95cec 24/62: Table: Completion, better POSIX portability

[Mohammad Akhlaghi]

branch: master
commit 7c95cecb972b20e30c94db1dce34a2eaee7ee29a
Author: Pedram Ashofteh Ardakani <pedramardakani@pm.me>
Commit: Mohammad Akhlaghi <mohammad@akhlaghi.org>

    Table: Completion, better POSIX portability
    
    Until now, portability was not heavily checked. With this commit,
    warnings from 'shellcheck' are taken into consideration and acted upon
    wherever possible.
    
    Added few words about my thoughts on portability. In short, taking bash
    version 3+ (2004) into consideration should suffice since it looks like
    MacOS has bash 3.2 installed as its default shell environment.
    
    Use '#!/usr/bin/env bash' instead of '#/usr/bin/env bash'
    
    Fix redundancy of: '$ echo $(cmd)' with 'cmd'
    
    Remove 'local' variables as it is not POSIX portable
    
    TODO: There are more warnings that need tending to.
---
 bin/table/completion.sh | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/bin/table/completion.sh b/bin/table/completion.sh
index 23b0510..814eba3 100644
--- a/bin/table/completion.sh
+++ b/bin/table/completion.sh
@@ -1,4 +1,4 @@
-#/usr/bin/env bash
+#!/usr/bin/env bash
 
 # TODO: GNU Copyright ...
 # Original Author:
@@ -21,6 +21,15 @@
 # command on the current commandline, there should be no completion
 # suggestions.
 
+# A thought on portability and obeying POSIX standards. This autocomplete
+# script should be compatible to bash 3.0 (2004) and newer. That is because
+# the MacOS standard is still around bash 3.2. Some commands such as
+# '[[ =~', 'complete', arrays, etc. are not POSIX compatible. But they are bash
+# built-in.
+
+# TODO: There should be some way to keep autocomplete from crashing in
+# older systems.
+
 # TIP: Run the command below to initialize the bash completion feature for
 # this specific program (i.e. astcosmiccal):
 # $ source astcosmiccal-completion.bash
@@ -41,7 +50,7 @@ db=0 # Set 0 for printing debug messages, else set to 1
 _gnuastro_autocomplete_get_fits_hdu(){
     # Accepts a fits filename as input and echoes its headers
     if [ -f "$1" ]; then
-        echo "$($ASTFITS --quiet $1 | awk '{print $2}')"
+        $ASTFITS --quiet "$1" | awk '{print $2}'
     fi
 }
 
@@ -49,8 +58,8 @@ _gnuastro_autocomplete_list_fits_hdu(){
     # Checks for the current fits file and puts its headers into
     # completion suggestions
     if [ -f "$1"  ]; then
-        local list="$(_gnuastro_autocomplete_get_fits_hdu $1)"
-        COMPREPLY=($(compgen -W "${list[@]}"))
+        list=$(_gnuastro_autocomplete_get_fits_hdu "$1")
+        COMPREPLY=($(compgen -W "$list"))
     fi
 }
 
@@ -79,7 +88,7 @@ _gnuastro_autocomplete_get_fits_name(){
     # Get the first fits file among the command line and put it into the
     # $comp_fits_name variable
     # TODO: How about all other fits file extensions?
-    local file_name="$(echo ${COMP_WORDS[@]} | awk -v 
regex="[a-zA-Z0-9]*.[fF][iI][tT][sS]" 'match($0, regex) {print substr($0, 
RSTART, RLENGTH)}')"
+    file_name="$(echo ${COMP_WORDS[@]} | awk -v 
regex="[a-zA-Z0-9]*.[fF][iI][tT][sS]" 'match($0, regex) {print substr($0, 
RSTART, RLENGTH)}')"
     if [ -f "$file_name" ]; then
         # Check if file_name is actually an existing fits file. This
         # prevents other functions from failing and producing obscure error
@@ -102,7 +111,7 @@ _gnuastro_autocomplete_get_fits_columns(){
         # start with numbers. If so, there will be an unwanted '(hdu:'
         # printed in the results. Here, 'awk' will print the second column
         # in lines that start with a number.
-        echo "$($ASTTABLE --information $1 | awk 'NR>2' | awk '/^[0-9]/ {print 
$2}')"
+        $ASTTABLE --information "$1" | awk 'NR>2' | awk '/^[0-9]/ {print $2}'
     fi
 }
 
@@ -110,7 +119,7 @@ _gnuastro_autocomplete_list_fits_columns(){
     # Accept a fits file name as the first argument ($1). Read and suggest
     # its column names. If the file does not exist, pass.
     if [ -f "$1" ]; then
-        local list="$(_gnuastro_autocomplete_get_fits_columns $1)"
+        list=$(_gnuastro_autocomplete_get_fits_columns "$1")
         COMPREPLY=($(compgen -W "$list"))
     fi
 }
@@ -130,31 +139,31 @@ _gnuastro_autocomplete_list_options(){
     # types. For example the 'asttable' program can either accept a fits
     # file or various short/long options as its first argument. In this
     # case, autocompletion suggests both.
-    local list=$("$1" --help | awk -v regex=" --+[a-zA-Z0-9]*=?" 'match($0, 
regex) {print substr($0, RSTART, RLENGTH)}')
+    list=$("$1" --help | awk -v regex=" --+[a-zA-Z0-9]*=?" 'match($0, regex) 
{print substr($0, RSTART, RLENGTH)}')
     COMPREPLY+=($(compgen -W "$list" -- "$word"))
 }
 
 _gnuastro_asttable_completions(){
 
     # TODO: @@
-    local PROG_NAME="asttable";
+    PROG_NAME="asttable";
 
-    local PROG_ADDRESS="$PREFIX/$PROG_NAME";
+    PROG_ADDRESS="$PREFIX/$PROG_NAME";
 
     # Initialize the completion response with null
     COMPREPLY=();
 
     # Variable "word", is the current word being completed
-    local word="${COMP_WORDS[COMP_CWORD]}";
+    word="${COMP_WORDS[COMP_CWORD]}";
 
     # Variable "prev" is the word just before the current word
-    local prev="${COMP_WORDS[COMP_CWORD-1]}";
+    prev="${COMP_WORDS[COMP_CWORD-1]}";
 
     # A quick check to see if there is already a fits file name invoked in
     # the current commandline. This means the order of commands does matter
     # in this bash completion. If we do not want this, we should implement
     # another method for suggesting completions.
-    local fits_name="$(_gnuastro_autocomplete_get_fits_name)"
+    fits_name="$(_gnuastro_autocomplete_get_fits_name)"
 
     # TODO: Prettify the code syntax, shorter ones on top
     case "$prev" in
@@ -191,8 +200,9 @@ _gnuastro_asttable_completions(){
     esac
 
     if [[ ! "${COMPREPLY[@]}" =~ "=" ]]; then
-        # '[[' and 'compopt' work for bash 4+
-        # TODO: Find workaround for older bash
+        # '[[' and 'compopt' work for bash 3+ so it should be portable to
+        # systems younger than 2004.
+        # https://mywiki.wooledge.org/BashFAQ/061
         compopt +o nospace
     fi
 
@@ -205,7 +215,7 @@ _gnuastro_asttable_completions(){
 >>> word: '$word' -- \$2: '$2'
 >>> fits_name: '$fits_name'
 EOF
-        printf ">>> line: ${COMP_LINE[@]}"
+        printf ">>> line: %s" "$COMP_LINE"
     fi
 
 }