Added first draft, pre-testing version of the config function,

which aims to make querying and configuring scripts in bash
not a pain in the ass.

lib/config.sh

@@ -0,0 +1,169 @@
+#/bin/bash
+
+# doc cfg {
+#
+# NAME
+#   cfg
+# 
+# DESCRIPTION
+#   Reads and writes config files delimited by tabs, like fstab, using awk.
+# 
+# USAGE
+#  _cfg <command> <arg>
+#
+# COMMANDS
+#   set-file <path/to/file>
+#       Sets path to file
+#
+#   create <column-names>
+#       Creates config file and assigns <column-names>.
+#
+#   print <column-name> <row-no>
+#       Prints value from <column-name> and <row-no>.  
+# 
+#   change <column-name> <row-no> <value> 
+#       Assigns new <value> to <column-name> and <row-no>.
+#
+#   drop <row|column} {no|name}
+#       Drops <row-no> or <column-name>.
+#
+#   insert <value-for-col1> <value-for-col2> <...>
+#       Inserts new row with a value per column. Number of arguments must match number of columns.
+#
+#   query <conditional>
+#       Queries which <row-no(s)> fits the <conditional>.
+#   
+#
+# CONDITIONALS
+#   
+#   
+#    
+# EXIT VALUES
+#   0   Success
+#   1   Syntax or usage error
+#   2   File not found
+#   3   File already present
+#   4   Row or column not found
+#   5   Row or column already has value
+#
+# }
+
+_cfg() {
+    # Sanity check and command parser
+    [[ ! -z ${1+x} ]] && {_msg ECHO "_cfg(): Expected command"; return 1}
+    local cmdList="(set-file create print change drop insert query)"
+    local CMD=${1}; shift
+    [[ ! _if_array_contains ${CMD} ${cmdList[@]} ]] && {_msg ECHO "_cfg(): Command specified not valid; return 1"}
+
+    # Dispatcher
+    _cfg_$(sed 's|-|_|' <<<"${CMD}") ${@}
+}
+
+_cfg_column_to_nf() {
+    # Argument parser and sanity check
+    [[ ! -z ${1+x} ]] && {_msg ECHO "_cfg(): Expected column name"; return 1}
+    local COLUMN=${1}
+
+    # Queries list of columns
+    local columnList=(all $(awk 'BEGIN {FS="\t"; OFS="\t"}; {if (NR = 0) {print '${0}'}}' ${_CFG_PATH}))
+    
+    # Checks if queried ${COLUMN} exists
+    if [ if ! _if_array_contains ${COLUMN} ${columnList[@]} ]; then
+        _msg ECHO "_cfg_column_to_nf(): Column does not exist"
+        return 1
+    else
+        # Finds what NF is associated with ${COLUMN}
+        local COUNT=0
+        for column ${columnList[@]}; do
+            [[ "${COLUMN}" == "${column}" ]] && echo "${COUNT}"
+            local COUNT=$(( ${COUNT} + 1 ))
+            return 0
+        done
+    fi
+}
+
+_cfg_set_file() {
+    # Argument parser and sanity check
+    [[ $# != 1 ]] && {_msg ECHO "_cfg_set_file(): Expected 1 argument"; return 1}
+    
+    # Sets _CFG_PATH globally
+    _CFG_PATH="${1}"
+    _CFG_TMP_PATH="$(sed 's|\(.*\)\/|\1/.|' <<<"${CFG_PATH}")"
+}
+
+_cfg_create() {
+    # Argument parser and sanity check
+    [[ ! -z ${1+x} ]] && {_msg ECHO "_cfg_create(): Expected argument"; return 1}
+    local colList=(${@})
+
+    # Creates config file
+    printf "%s\t" ${colList[@]} >> ${_CFG_PATH}
+}
+
+_cfg_print() {
+    # Argument parser and sanity check
+    [[ $# != 2 ]] && {_msg ECHO "_cfg_print(): Expected 2 arguments"; return 1}
+    local COLUMN=${1}
+    local ROW=${2}
+
+    # Prints row of ${_CFG_PATH}
+    awk 'BEGIN {FS="\t"; OFS="\t"}; {if (NR='${ROW}') {print $'$(_cfg_column_to_nf ${COLUMN})'}}' "${_CFG_PATH}"
+}
+
+_cfg_change() {
+    # Argument parser and sanity check    
+    [[ $# != 3 ]] && {_msg ECHO "_cfg_change(): Expected 3 arguments"; return 1}
+    local COLUMN=${1}
+    local ROW=${2}
+    local VALUE=${3}
+    [[ ! _if_is_integer ${ROW} ]] && {_msg ECHO "_cfg_change(): Expected integer; return 1"}
+    
+    # Writes new version of file
+    awk 'BEGIN {OFS="\t"}; {if (NR == '${ROW}') {$'$(_cfg_column_to_nf ${COLUMN})'='${VALUE}'} {print $0}}' "${_CFG_PATH}" > ${_CFG_TMP_PATH} && mv ${_CFG_TMP_PATH} ${_CFG_PATH}
+    
+}
+
+_cfg_drop() {
+    # Argument parser and sanity check
+    [[ -z $# != 2 ]] && {_msg ECHO "_cfg_drop(): Expected 2 arguments"; return 1}
+    local SUBCMD=${1}; shift
+    [[ ! _if_array_contains ${SUBCMD} row column ]] && {_msg ECHO "_cfg_drop(): Expected 'row' or 'column' as subcommand"; return 1}
+
+    # Dispatcher
+    _cfg_drop_${SUBCMD} ${1}
+}
+
+_cfg_drop_row() {
+    # Argument parser and sanity check
+    local ROW=${1}
+    [[ ${ROW} -mt $(awk 'BEGIN {FS="\t"; OFS="\t"}; {print NR}' ${_CFG_PATH}) ]] && {_msg ECHO "_cfg_drop_row(): Row number higher than available"}
+    
+    # Writes new version of file
+    awk 'BEGIN {OFS="\t"}; {if (NR == '${ROW}') {$0="\b") {print $0}}' ${_CFG_PATH} > ${_CFG_TMP_PATH} && mv ${_CFG_TMP_PATH} ${_CFG_PATH}
+
+}
+
+_cfg_drop_column() {
+    local COLUMN=${1}
+    local NF=$(_cfg_column_to_nf "${COLUMN}")
+
+    # Writes new version of file
+    awk 'BEGIN {OFS="\t"}; {$'${NF}'="\b"; print &0}' ${_CFG_PATH} > ${_CFG_TMP_PATH} && mv ${_CFG_TMP_PATH} ${_CFG_PATH}
+}
+   
+_cfg_insert() {
+    # Argument parser and sanity check
+    local valueList=(${@})
+    local COLUMN_NO=$(awk 'BEGIN{OFS="\t"}; {if (NR == 1) {print NF}}' ${_CFG_PATH})
+    [[ "${#valueList[@]}" =! "${COLUMN_NO}" ]] && {_msg ECHO "_cfg_insert(): Number of arguments must be equal to ${COLUMN_NO}"; return 1}
+
+    # Write row into file
+    printf "%s\t" ${valueList[@]} >> ${_CFG_PATH}
+}
+
+_cfg_query() {
+    # Argument parser and sanity check
+    local CONDITION=${1}
+    
+    awk 'BEGIN {FS="\t"; OFS="\t"}; {if ('${CONDITION}') {print NR}}' "{_CFG_PATH}"
+}