adding function to source bash scripts

functions/source_script.fish

+# Cloned from https://github.com/fish-shell/fish-shell/issues/522
+
+function source_script --description 'Source sh/csh file'
+  set -l ext
+  set -l type
+
+  while true
+    switch $argv[1]
+      case '--sh'
+      set type sh
+      case '--csh'
+      set type csh
+      case '--bash'
+      set type bash
+      case '--ext'
+      set ext 1
+      case '*'
+      break
+    end
+    set -e argv[1]
+  end
+
+  if not test "$type"
+    for f in $argv
+      switch $f
+        case '*.sh'
+        set type bash
+        break
+        case '*.csh' '*.tcsh'
+        set type csh
+        break
+      end
+    end
+  end
+
+  set -l exe
+  set -l source
+
+  switch "$type"
+    case bash
+    set exe /bin/bash
+    set source .
+    case sh
+    set exe /bin/sh
+    set source .
+    case csh
+    set exe /bin/tcsh
+    set source source
+    case '*'
+    echo Unknown source type for "'$argv'"
+  end
+
+  if test "$ext"
+    eval "exec $exe -c '$source $argv; exec fish'"
+  else
+    set -l f1 (mktemp -t tmp.XXXXXXXXXX)
+    set -l f2 (mktemp -t tmp.XXXXXXXXXX)
+    eval $exe -c "'env | sort > $f1; $source $argv; env | sort > $f2'"
+
+    set -l filter "(^[^\+-]|^\+\+\+|^---|^[\+-]_|^[\+-]PIPESTATUS|^[\+-]COLUMNS)"
+    set -l pattern 's/[:]\{0,1\}\([^:]\+\)/"\1" /g'
+
+    set -l IFS '='
+    set -l diffopts --old-line-format '-=%L' --new-line-format '+=%L' --unchanged-line-format ''
+    diff $diffopts $f1 $f2 | grep -vE $filter | while read -l state var value
+      switch $state$var
+        case -PATH
+        continue
+
+        case +PATH
+        eval set value (echo $value | tr : ' ')
+        for pt in $value
+            contains $pt $PATH; and continue
+            if not test -d $pt
+                echo "Unable to add '$pt' to \$PATH. Check existance."
+                continue
+            end
+            #echo set -gx PATH $PATH $pt
+            set -gx PATH $PATH $pt >  /dev/null
+        end
+
+        case '-*'
+        #echo unset $var
+        set -e $var
+
+        case '+*'
+        eval set -gx $var (echo $value | sed $pattern)
+        #echo Set $var to: (echo $value | sed $pattern)
+
+        case '*'
+        echo Source error! Invalid case "'$state$var'"
+      end
+    end
+
+    rm $f1 $f2 > /dev/null
+  end
+end