Refactor prompt_command

1 files changed, 108 insertions, 69 deletions

diff --git a/bashrc b/bashrc
index 5c774e7..725b34a 100644
--- a/bashrc
+++ b/bashrc
@@ -1,18 +1,85 @@
+########################################################################
+# Colour definitions for parts of $PS1.
+
+
+# Do we even have a terminal we can do things to?
+we_have_term()
+{
+    [ "$TERM" ] && [ "$TERM" != dumb ]
+}
+
+
+raw_termattr()
+{
+    if we_have_term
+    then
+        for attr in "$@"
+        do
+            case "$attr" in
+                normal)
+                    tput sgr0
+                    ;;
+                red)
+                    tput setaf 1
+                    ;;
+                bold)
+                    tput bold
+                    ;;
+            esac
+        done
+    fi
+}
+
+
+# Output terminal attribute changing sequence, if there's a terminal.
+# Also output output bash $PS1 sequences to tell bash it's
+# non-printing characters.
+termattr()
+{
+    printf '\['
+    raw_termattr "$@"
+    printf '\]'
+}
+
+
+
+########################################################################
+# Collect info to show in $PS1
+
+
+taskwarrior_context()
+{
+    task context list | awk '$NF == "yes" { print $1 }'
+}
+
+
+# Context for git and Debian packging: QvarnLabs?
+QL()
+{
+    case "$DEBEMAIL" in
+    *@qvarnlabs.com) printf '[QL] ' ;;
+    esac
+}
+
+
 find_git_root()
 {
-    (set -e
-    while [ "$(pwd)" != / ]
-    do
-        if [ -d .git ]
-        then
-            pwd
-            break
+    (
+        set -e
+        while [ "$(pwd)" != / ]
+        do
+            if [ -d .git ]
+            then
+                pwd
+                break
         else
             cd ..
-        fi
-    done)
+            fi
+        done
+    )
 }
 
+
 is_git_repo()
 {
     case "$(find_git_root)" in
@@ -21,6 +88,7 @@ is_git_repo()
     esac
 }
 
+
 get_git_branch()
 {
     git branch --no-color | 
@@ -35,88 +103,60 @@ get_git_branch()
     '
 }
 
-git_prompt_part()
-{
-    if is_git_repo
-    then
-        echo -n "\\[$(normal_mode)\\][$(get_git_branch)]\\[$(start_bold)\\]"
-    fi
-}
 
-QL()
-{
-    case "$DEBEMAIL" in
-    *@qvarnlabs.com) echo '[QL] ' ;;
-    esac
-}
+########################################################################
+# Dynamically change $PS1 or output other things just before the prompt.
+
 
-task_context()
+wrap_if_nonempty()
 {
-    local context="$(task context list | awk '$NF == "yes" { print $1 }')"
-    case "$context" in
-    ?*) echo "{{ $context }} " ;;
-    esac
-}
+    local thing="$1"
+    local before="$2"
+    local after="$3"
 
-iconpart="`whoami`@`hostname`: "
-titlepart="`whoami`@`hostname` -- "
-prompt_command() { 
-    prompt_status=$?
-    if [ -r /etc/debian_chroot ]
-    then
-        debian_chroot="$(cat /etc/debian_chroot) "
-    else
-        debian_chroot=""
-    fi
-    if [ $prompt_status != 0 ]
+    if [ -n "$thing" ]
     then
-            echo "$(start_error)[status $prompt_status]$(normal_mode)"
+        printf '%s%s%s' "$before" "$thing" "$after"
     fi
-    base="`basename "$PWD"`"
-    PS1="\\[$(start_error)$(task_context)$(QL)$(start_bold)\\]\\u@\\h$(git_prompt_part)\\[$(basename_mode)\\](\W)\\[$(start_bold)\\]\\$ \\[$(normal_mode)\\]"
 }
 
-we_have_term()
-{
-    [ "$TERM" ] && [ "$TERM" != dumb ]
-}
 
-basename_mode()
+define_ps1()
 {
-    if we_have_term
-    then
-        tput sgr0
-        tput setaf 4
-    fi
-}
+    wrap_if_nonempty "$(taskwarrior_context)" "$(termattr bold)" "$(termattr normal) "
+    wrap_if_nonempty "$(QL)" "$(termattr red bold)" "$(termattr normal)"
 
-start_error()
-{
-    if we_have_term
+    if is_git_repo
     then
-        tput bold
-        tput setaf 1
+        wrap_if_nonempty "$(get_git_branch)" "$(termattr bold)[" "]$(termattr normal)"
     fi
+
+    printf '(\w)\$ '
 }
 
-start_bold()
+
+tell_about_exit_code()
 {
-    if we_have_term
+    local exit_code="$1"
+    if [ "$exit_code" != 0 ]
     then
-        tput sgr0
-        tput bold
+        raw_termattr red
+        printf '[PREVIOUS COMMAND EXIT: %s]\n' "$exit_code"
+        raw_termattr normal
     fi
 }
 
-normal_mode()
-{
-    if we_have_term
-    then
-        tput sgr0
-    fi
+
+export PROMPT_COMMAND=prompt_command
+prompt_command() { 
+    tell_about_exit_code "$?"
+    PS1="$(define_ps1)"
 }
 
 
+
+###############
+
 ulimit -c unlimited
 umask 002
 
@@ -130,7 +170,6 @@ export PAGER=less
 export LESSCHARSET=utf-8
 export HISTCONTROL=ignoredups
 export PATH="$PATH:$HOME/bin"
-export PROMPT_COMMAND=prompt_command
 export DEBEMAIL=liw@liw.fi
 export VIRSH_DEFAULT_CONNECT_URI=qemu:///system
 export LANG=en_GB.UTF-8