Add: nix-script repl

This is a combination of 23 commits:

    * Add first draft for nix-shell repl
    * Remove functions which are in nix-utils.sh
    * Minify if-then-exit
    * Remove sudo run... why do I actually have this?
    * Include helpers
    * Add help text
    * Remove old arguments in parsing code
    * Dont print on stderr, do debugging output here
    * Remove explain checker, use dbg() as output function
    * Fix checker
    * Use bash to print
    * Use "exit" or "quit" to exit nix-repl
    * Remove doubled caller code
    * Move: script_for() function to helpers
    * Remove old variables
    * Fix bash call
    * move all_commands() function to nix-utils.sh
    * Formatted and extended all_commands() function
    * Lists executables only.
    * Shorten error message
    * Add helper to check whether a string contains a string
    * Add possibility to execute simple bash commands in repl
    * The more debug output, the better
    * More things, we should really squash this stuff

3 files changed, 127 insertions, 16 deletions

diff --git a/nix-script b/nix-script
index 3860f20..5bdfe15 100755
--- a/nix-script
+++ b/nix-script
@@ -25,15 +25,6 @@ VERBOSE=0
 
 source $(dirname ${BASH_SOURCE[0]})/nix-utils.sh
 
-#
-# Get the name of the script file for the command passed as argument
-#
-# Does not check whether the file exists.
-#
-script_for() {
-    echo "$(dirname ${BASH_SOURCE[0]})/nix-script-${1}.sh"
-}
-
 SHIFT_ARGS=0
 
 #
@@ -56,13 +47,6 @@ shift_n() {
 }
 
 #
-# List all available commands
-#
-all_commands() {
-    find $(dirname ${BASH_SOURCE[0]}) -type f -name "nix-script-*.sh"
-}
-
-#
 # Parse the arguments for this script
 #
 for cmd
diff --git a/nix-script-repl.sh b/nix-script-repl.sh
new file mode 100755
index 0000000..21252d5
--- /dev/null
+++ b/nix-script-repl.sh
@@ -0,0 +1,101 @@
+#!/usr/bin/env bash
+
+source $(dirname ${BASH_SOURCE[0]})/nix-utils.sh
+
+usage() {
+    cat <<EOS >&2
+    $(help_synopsis "${BASH_SOURCE[0]}" "[-h] [--shell]")
+
+    --shell     If a command is not available, try to execute it in this shell
+    -h          Show this help and exit
+
+    All nixos-script subcommands and their respective arguments are available.
+
+    In addition to the normal commands, these commands are available:
+
+        list        | Lists all available commands
+
+$(help_end "repl")
+EOS
+}
+
+Color_Off='\e[0m'
+Red='\e[0;31m'
+Green='\e[32m'
+
+__SHELL=0
+
+for arg
+do
+    case $arg in
+
+        --shell)
+            __SHELL=1
+            dbg "__SHELL = $__SHELL"
+            ;;
+
+        "-h")
+            usage
+            exit 0
+            ;;
+
+        *)
+            ;;
+    esac
+done
+
+run() {
+    dbg $*; $*
+}
+
+__exists() {
+    dbg "Exists '$1'? ..."
+    which $1 >/dev/null 2>/dev/null
+}
+
+prompt() {
+    echo -en "${Green}nix-script repl >${Color_Off} "
+}
+
+__run_if_exists() {
+    [[ $(__exists $1) ]] && run $* || false
+}
+
+__list() {
+    dbg "Listing commands"
+    caller_util_list_subcommands_for "nix-script"
+}
+
+prompt
+while read COMMAND ARGS
+do
+    [[ $COMMAND =~ "quit" || $COMMAND =~ "exit" ]] && break
+    [[ $COMMAND =~ "help" ]] && usage  && prompt && continue
+    [[ $COMMAND =~ "list" ]] && __list && prompt && continue
+
+    dbg "Got '$COMMAND' with args '$ARGS'"
+    stdout "Searching for script for '$COMMAND'"
+    SCRIPT=$(script_for $COMMAND)
+
+    if [[ ! -f $SCRIPT || ! -x $SCRIPT ]]
+    then
+        dbg "Not available or executable: $COMMAND"
+        #
+        # Checks whether the args include bash-specific things like || or &&, as
+        # these cannot be executed by nix-script repl by now, and prints a
+        # warning and does not allow execution of these.
+        #
+        if [[ "$ARGS" =~ ^[a-zA-Z0-9_\ ]*$ && $__SHELL -eq 1 ]]
+        then
+            dbg "Executing: '$COMMAND $ARGS'"
+            $COMMAND $ARGS
+        fi
+    else
+        stdout "Calling: '$COMMAND $ARGS'"
+        bash $SCRIPT $ARGS
+    fi
+    prompt
+done
+
+stdout "Ready. Bye-Bye!"
+
diff --git a/nix-utils.sh b/nix-utils.sh
index 9e2fd3c..a34a2ee 100644
--- a/nix-utils.sh
+++ b/nix-utils.sh
@@ -6,6 +6,13 @@ Yellow='\e[0;33m'
 Green='\e[0;32m'
 
 #
+# Check whether a string (2nd arg) contains a substring (1st arg)
+#
+stringcontains() {
+    [ -z "${2##*$1*}" ]
+}
+
+#
 # Print on stderr, in red
 #
 stderr() {
@@ -28,6 +35,25 @@ stdout() {
 }
 
 #
+# List all available commands as script path
+#
+all_commands() {
+    find $(dirname ${BASH_SOURCE[0]}) \
+        -type f \
+        -executable \
+        -name "nix-script-*.sh"
+}
+
+#
+# Get the name of the script file for the command passed as argument
+#
+# Does not check whether the file exists.
+#
+script_for() {
+    echo "$(dirname ${BASH_SOURCE[0]})/nix-script-${1}.sh"
+}
+
+#
 # Get the command name from a script path
 #
 scriptname_to_command() {