Allow coloring contexts and projects independently

Because @contexts and +projects are metadata as much as they are text,
it can be nice to highlight them independently of the coloring of the line
that contains them.  This is tough to do correctly in
a TODOTXT_FINAL_FILTER because doing it at that layer requires
re-parsing the text of the line to find the appropriate PRI_$x color to
reset to after coloring the word, or trying to reverse engineer where
the color codes inserted by todo.sh end and the user's text begins (and
vice versa).

Closes #119

tests/t1360-ls-project-context-highlighting.sh

@@ -0,0 +1,91 @@
+#!/bin/bash
+#
+
+test_description='highlighting projects and contexts
+
+This test checks the highlighting (with colors) of projects and contexts.
+'
+. ./test-lib.sh
+
+# Prioritized tasks with projects and contexts
+cat > todo.txt <<EOF
+(A) prioritized @con01 context
+(B) prioritized +prj02 project
+(C) prioritized context at EOL @con03
+(D) prioritized project at EOL +prj04
++prj05 non-prioritized project at BOL
+@con06 non-prioritized context at BOL
+multiple @con_ @texts and +pro_ +jects
+non-contexts: seti@home @ @* @(foo)
+non-projects: lost+found + +! +(bar)
+EOF
+
+# config file specifying COLOR_PROJECT and COLOR_CONTEXT
+#
+TEST_TODO_LABEL_COLORS=todo-colors.cfg
+cat todo.cfg > "$TEST_TODO_LABEL_COLORS"
+
+echo "export COLOR_CONTEXT='\\\\033[1m'" >>"$TEST_TODO_LABEL_COLORS"
+echo "export COLOR_PROJECT='\\\\033[2m'" >>"$TEST_TODO_LABEL_COLORS"
+
+test_todo_session 'highlighting for contexts and projects' <<'EOF'
+>>> todo.sh -d "$TEST_TODO_LABEL_COLORS" ls
+1 (A) prioritized @con01 context
+2 (B) prioritized +prj02 project
+3 (C) prioritized context at EOL @con03
+4 (D) prioritized project at EOL +prj04
+5 +prj05 non-prioritized project at BOL
+6 @con06 non-prioritized context at BOL
+7 multiple @con_ @texts and +pro_ +jects
+8 non-contexts: seti@home @ @* @(foo)
+9 non-projects: lost+found + +! +(bar)
+--
+TODO: 9 of 9 tasks shown
+EOF
+
+test_todo_session 'suppressing highlighting for contexts and projects' <<'EOF'
+>>> todo.sh -p -d "$TEST_TODO_LABEL_COLORS" ls
+1 (A) prioritized @con01 context
+2 (B) prioritized +prj02 project
+3 (C) prioritized context at EOL @con03
+4 (D) prioritized project at EOL +prj04
+5 +prj05 non-prioritized project at BOL
+6 @con06 non-prioritized context at BOL
+7 multiple @con_ @texts and +pro_ +jects
+8 non-contexts: seti@home @ @* @(foo)
+9 non-projects: lost+found + +! +(bar)
+--
+TODO: 9 of 9 tasks shown
+EOF
+
+test_todo_session 'suppressing display of contexts' <<'EOF'
+>>> todo.sh -@ -d "$TEST_TODO_LABEL_COLORS" ls
+1 (A) prioritized context
+2 (B) prioritized +prj02 project
+3 (C) prioritized context at EOL
+4 (D) prioritized project at EOL +prj04
+5 +prj05 non-prioritized project at BOL
+6 non-prioritized context at BOL
+7 multiple and +pro_ +jects
+8 non-contexts: seti@home @
+9 non-projects: lost+found + +! +(bar)
+--
+TODO: 9 of 9 tasks shown
+EOF
+
+test_todo_session 'suppressing display of projects' <<'EOF'
+>>> todo.sh -+ -d "$TEST_TODO_LABEL_COLORS" ls
+1 (A) prioritized @con01 context
+2 (B) prioritized project
+3 (C) prioritized context at EOL @con03
+4 (D) prioritized project at EOL
+5 non-prioritized project at BOL
+6 @con06 non-prioritized context at BOL
+7 multiple @con_ @texts and
+8 non-contexts: seti@home @ @* @(foo)
+9 non-projects: lost+found +
+--
+TODO: 9 of 9 tasks shown
+EOF
+
+test_done

todo.sh

@@ -615,6 +615,10 @@ 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.
+export COLOR_PROJECT=$NONE
+export COLOR_CONTEXT=$NONE
+
 # Default highlight colors.
 export COLOR_DONE=$LIGHT_GREY   # color for done (but not yet archived) tasks
 
@@ -730,8 +734,13 @@ if [ $TODOTXT_PLAIN = 1 ]; then
     PRI_X=$NONE
     DEFAULT=$NONE
     COLOR_DONE=$NONE
+    COLOR_PROJECT=$NONE
+    COLOR_CONTEXT=$NONE
 fi
 
+[[ "$HIDE_PROJECTS_SUBSTITUTION" ]] && COLOR_PROJECT="$NONE"
+[[ "$HIDE_CONTEXTS_SUBSTITUTION" ]] && COLOR_CONTEXT="$NONE"
+
 _addto() {
     file="$1"
     input="$2"
@@ -878,15 +887,38 @@ _format()
                 return color
             }
             {
+                clr = ""
                 if (match($0, /^[0-9]+ x /)) {
-                    print highlight("COLOR_DONE") $0 highlight("DEFAULT")
+                    clr = highlight("COLOR_DONE")
                 } else if (match($0, /^[0-9]+ \([A-Z]\) /)) {
                     clr = highlight("PRI_" substr($0, RSTART + RLENGTH - 3, 1))
-                    print \
-                        (clr ? clr : highlight("PRI_X")) \
-                        (ENVIRON["HIDE_PRIORITY_SUBSTITUTION"] == "" ? $0 : substr($0, 1, RLENGTH - 4) substr($0, RSTART + RLENGTH)) \
-                        highlight("DEFAULT")
-                } else { print }
+                    clr = (clr ? clr : highlight("PRI_X"))
+                    if (ENVIRON["HIDE_PRIORITY_SUBSTITUTION"] != "") {
+                        $0 = substr($0, 1, RLENGTH - 4) substr($0, RSTART + RLENGTH)
+                    }
+                }
+                end_clr = (clr ? highlight("DEFAULT") : "")
+
+                prj_beg = highlight("COLOR_PROJECT")
+                prj_end = (prj_beg ? (highlight("DEFAULT") clr) : "")
+
+                ctx_beg = highlight("COLOR_CONTEXT")
+                ctx_end = (ctx_beg ? (highlight("DEFAULT") clr) : "")
+
+                gsub(/[ \t][ \t]*/, "\n&\n")
+                len = split($0, words, /\n/)
+
+                printf "%s", clr
+                for (i = 1; i <= len; ++i) {
+                    if (words[i] ~ /^[+].*[A-Za-z0-9_]$/) {
+                        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 {
+                        printf "%s", words[i]
+                    }
+                }
+                printf "%s\n", end_clr
             }
           '''  \
         | sed '''