Reorganise highlighter selection in less and cat

- LESSOPEN contains lesspipe{,sh} only
- ~/.lessfilter tries more highlighters
- cat-highlight processes each file independently
- cat-highlight tries to use ~/.lessfilter

.config/zsh/.zprofile

@@ -57,15 +57,7 @@ export PASSWORD_STORE_GENERATED_LENGTH="43"
 
 export LESS="--tabs=4 --RAW-CONTROL-CHARS --LONG-PROMPT"
 
-if command -v highlight > /dev/null; then
-    # ~/.lessfilter handles the highlighting
-    LESSOPEN="| $(command -v lesspipe) %s"
-    export CATOPEN="highlight --force --out-format=truecolor --style=base16/unikitty-reversible --stdout %s"
-elif command -v pygmentize > /dev/null; then
-    LESSOPEN="| $(command -v pygmentize) -f terminal16m -g -O style=paraiso-dark %s"
-elif command -v source-highlight > /dev/null; then
-    LESSOPEN="| $(command -v source-highlight) --failsafe --infer-lang --out-format=esc --style-file=esc.style --input=%s"
-elif command -v lesspipe > /dev/null; then
+if command -v lesspipe > /dev/null; then
     LESSOPEN="| $(command -v lesspipe) %s"
 elif command -v lesspipe.sh > /dev/null; then
     LESSOPEN="| $(command -v lesspipe.sh) %s"

.config/zsh/functions/cat-highlight

@@ -1,42 +1,54 @@
 #!/usr/bin/env zsh
-# Highlight cat output with either $CATOPEN or $LESSOPEN. The command needs to
-# have %s in it that will be replaced with all input files. Some programs that
-# are known to not work will be ignored in $LESSOPEN but not in $CATOPEN.
+# Highlight cat output with either $CATOPEN, ~/.lessfilter or $LESSOPEN. The
+# command needs to have %s in it that will be replaced with input files (one by
+# one). Some programs that are known to not work will be ignored in $LESSOPEN
+# but not in $CATOPEN.
 
 # Example:
 # export CATOPEN="highlight --force --out-format=truecolor --stdout %s"
 # alias cat='cat-highlight'
 
-setopt LOCAL_OPTIONS ERR_RETURN PIPE_FAIL
+setopt LOCAL_OPTIONS PIPE_FAIL
 
-# Check if we are in a terminal and a highlighter is defined
-if [[ -t 1 ]] && [[ -n "${CATOPEN}" || -n "${LESSOPEN}" ]]; then
-    if [[ -z "${CATOPEN}" ]]; then
-        # Programs that won't work with cat
-        local -a known_bad=("lesspipe" "pygmentize" "source-highlight")
-        for baddy in ${known_bad}; do
-            if [[ "${LESSOPEN}" =~ "${baddy}" ]]; then
-                \cat "${@}"
-                return ${?}
-            fi
-        done
-        local catopen="${LESSOPEN/|/}"
-    else
-        local catopen="${CATOPEN}"
-    fi
+# Check if we are in a terminal
+if [[ ! -t 1 ]]; then
+    \cat ${@}
+    return ${?}
+fi
 
-    local -a args
-    local -a files
-    for arg in ${@}; do
-        # Filter out file names
-        if [[ "${arg[1]}" != "-" ]]; then
-            files+=${(q)arg}
-        else
-            args+="${arg}"
+# Try to find highlighter
+if [[ -v CATOPEN && -n ${CATOPEN} ]]; then
+    local catopen=${CATOPEN}
+elif [[ -x ~/.lessfilter ]]; then
+    local catopen="~/.lessfilter %s"
+elif [[ -v LESSOPEN && -n ${LESSOPEN} ]]; then
+    local catopen="${LESSOPEN/|/}"
+    # Programs that won't work with cat
+    local -a known_bad=("lesspipe")
+    for baddy in ${known_bad}; do
+        if [[ ${LESSOPEN} =~ ${baddy} ]]; then
+            unset catopen
         fi
     done
-
-    eval "${catopen/\%s/${files}} | \cat ${args}"
-else
-    \cat "${@}"
 fi
+
+if [[ ! -v catopen ]]; then
+    \cat ${@}
+    return ${?}
+fi
+
+local -a args
+local -a files
+for arg in ${@}; do
+    # Filter out file names
+    if [[ ${arg[1]} != "-" ]]; then
+        files+=${(q)arg}
+    else
+        args+=${arg}
+    fi
+done
+
+for file in ${files}; do
+    eval "${catopen/\%s/${file}}" 2>& -
+    [[ ${?} -ne 0 ]] && \cat ${file}
+done | \cat ${args}

.lessfilter

@@ -4,14 +4,27 @@
 
 setopt LOCAL_OPTIONS ERR_RETURN NO_UNSET PIPE_FAIL
 
-command -v highlight > /dev/null
-file="${1}"
+local file="${1}"
+local ret
+local output
 
-local output="$(highlight --force \
-                          --out-format=truecolor \
-                          --style=base16/unikitty-reversible \
-                          --stdout "${file}")"
-ret=${?}
+if type highlight >& -; then
+    output="$(highlight --force \
+                        --out-format=truecolor \
+                        --style=base16/unikitty-reversible \
+                        --stdout "${file}")"
+    ret=${?}
+elif type pygmentize >& -; then
+    output="$(pygmentize -f terminal16m -g -O style=paraiso-dark ${file})"
+    ret=${?}
+elif type source-highlight >& -; then
+    output="$(source-highlight --failsafe \
+                               --infer-lang \
+                               --out-format=esc \
+                               --style-file=esc.style \
+                               --input=${file})"
+    ret=${?}
+fi
 [[ ${ret} -eq 0 ]] || return ${ret}
 
 # Try to catch when the output is just the magic string