Highlighting of dates, metadata and item numbers (todotxt#264)

* add highlighting of dates, item numbers, and metadata

* add test for highlighting of dates, item numbers, and metadata

Co-authored-by: Ali Karbassi <ali@karbassi.com>

tests/t1380-ls-date-number-metadata-highlighting.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+#
+
+test_description='highlighting date, item numbers and metadata
+
+This test checks the highlighting (with colors) of dates, item numbers and metadata
+'
+. ./test-lib.sh
+
+# Tasks with dates and metadata
+cat > todo.txt <<EOF
+2018-11-11 task with date
+task with metadata due:2018-12-31
+task without date and without metadata
+EOF
+
+# config file specifying COLOR_PROJECT and COLOR_CONTEXT
+#
+TEST_TODO_LABEL_COLORS=todo-colors.cfg
+cat todo.cfg > "$TEST_TODO_LABEL_COLORS"
+
+echo "export COLOR_DATE='\\\\033[0;31m'" >>"$TEST_TODO_LABEL_COLORS"
+echo "export COLOR_META='\\\\033[0;32m'" >>"$TEST_TODO_LABEL_COLORS"
+echo "export COLOR_NUMBER='\\\\033[0;34m'" >>"$TEST_TODO_LABEL_COLORS"
+
+test_todo_session 'highlighting for date, item numbers and metadata' <<'EOF'
+>>> todo.sh -d "$TEST_TODO_LABEL_COLORS" ls
+1 2018-11-11 task with date
+2 task with metadata due:2018-12-31
+3 task without date and without metadata
+--
+TODO: 3 of 3 tasks shown
+EOF
+
+
+test_todo_session 'suppressing highlighting for date, item numbers and metadata' <<'EOF'
+>>> todo.sh -p -d "$TEST_TODO_LABEL_COLORS" ls
+1 2018-11-11 task with date
+2 task with metadata due:2018-12-31
+3 task without date and without metadata
+--
+TODO: 3 of 3 tasks shown
+EOF
+
+test_done

todo.cfg

@@ -62,10 +62,17 @@ export REPORT_FILE="$TODO_DIR/report.txt"
 #
 # export COLOR_DONE=$LIGHT_GREY
 
-# There is highlighting for projects and contexts.
+# There is highlighting for projects, contexts, dates, and item numbers.
 #
 # export COLOR_PROJECT=$RED
 # export COLOR_CONTEXT=$RED
+# export COLOR_DATE=$BLUE
+# export COLOR_NUMBER=$LIGHT_GRAY
+
+# There is highlighting for metadata key:value pairs e.g.
+# DUE:2006-08-01 or note:MYNOTE
+#
+# export COLOR_META=$CYAN
 
 # === BEHAVIOR ===
 

todo.sh

@@ -650,9 +650,12 @@ export PRI_B=$GREEN         # color for B priority
 export PRI_C=$LIGHT_BLUE    # color for C priority
 export PRI_X=$WHITE         # color unless explicitly defined
 
-# Default project and context colors.
+# Default project, context, date, item number, and metadata key:value pairs colors.
 export COLOR_PROJECT=$NONE
 export COLOR_CONTEXT=$NONE
+export COLOR_DATE=$NONE
+export COLOR_NUMBER=$NONE
+export COLOR_META=$NONE
 
 # Default highlight colors.
 export COLOR_DONE=$LIGHT_GREY   # color for done (but not yet archived) tasks
@@ -795,6 +798,9 @@ if [ $TODOTXT_PLAIN = 1 ]; then
     COLOR_DONE=$NONE
     COLOR_PROJECT=$NONE
     COLOR_CONTEXT=$NONE
+    COLOR_DATE=$NONE
+    COLOR_NUMBER=$NONE
+    COLOR_META=$NONE
 fi
 
 [[ "$HIDE_PROJECTS_SUBSTITUTION" ]] && COLOR_PROJECT="$NONE"
@@ -971,15 +977,30 @@ _format()
                 ctx_beg = highlight("COLOR_CONTEXT")
                 ctx_end = (ctx_beg ? (highlight("DEFAULT") clr) : "")
 
+                dat_beg = highlight("COLOR_DATE")
+                dat_end = (dat_beg ? (highlight("DEFAULT") clr) : "")
+
+                num_beg = highlight("COLOR_NUMBER")
+                num_end = (num_beg ? (highlight("DEFAULT") clr) : "")
+
+                met_beg = highlight("COLOR_META")
+                met_end = (met_beg ? (highlight("DEFAULT") clr) : "")
+
                 gsub(/[ \t][ \t]*/, "\n&\n")
                 len = split($0, words, /\n/)
 
                 printf "%s", clr
                 for (i = 1; i <= len; ++i) {
-                    if (words[i] ~ /^[+].*[A-Za-z0-9_]$/) {
+                    if (i == 1 && words[i] ~ /^[0-9]+$/ ) {
+                        printf "%s", num_beg words[i] num_end
+                    } else if (words[i] ~ /^[+].*[A-Za-z0-9_]$/) {
                         printf "%s", prj_beg words[i] prj_end
                     } else if (words[i] ~ /^[@].*[A-Za-z0-9_]$/) {
                         printf "%s", ctx_beg words[i] ctx_end
+                    } else if (words[i] ~ /^(19|20)[0-9]{2}-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])$/) {
+                        printf "%s", dat_beg words[i] dat_end
+                    } else if (words[i] ~ /^[[:alnum:]]+:[^ ]+$/) {
+                        printf "%s", met_beg words[i] met_end
                     } else {
                         printf "%s", words[i]
                     }