Initial commit

I'm doing content + generation in this ... who knows if it's smart, lol.

1 files changed, 66 insertions, 0 deletions

@@ -0,0 +1,66 @@
+#!/bin/sh
+# HAT TRICK
+# (C) 2022 C. Duckworth
+
+[ "x$DEBUG" = "xYES" ] && set -x
+
+: "${HTDAT:=$(date +%s)}"
+: "${HTTMP:=/tmp/ht}"; mkdir -p "$HTTMP"
+: "${HTENV:=$HTTMP/env-$HTDAT.sh}"
+: "${HTBOD:=$HTTMP/bod-$HTDAT.txt}"
+export HTDAT HTTMP HTENV HTBOD
+
+HT_TMPL_COUNT=1
+HT_TMPL_PRE=:
+
+print() { # print STRING...
+    ## A sane version of `echo`.
+    printf '%s\n' "$*"
+}
+
+htt() { # htt FILES...
+    # Like `cat`, but with templating.
+    ht_end="ht_main_$HTDAT_$HT_TMPL_COUNT" # be extra double sure
+    eval "$(print "cat <<$ht_end"; cat "$@"; print; print "$ht_end")"
+    HT_TMPL_COUNT=$(expr $HT_TMPL_COUNT + 1)
+}
+
+ht_build_env() { # ht_build_env FILE...
+    print "body() { cat \"$HTBOD\"; }" > "$HTENV"
+    while read -r line; do
+        case "$line" in
+            *@@*:*@@*) # "simple" metadata; just a string
+                print "$line" |
+                    sed 's/.*@@\([^:]*\): \?\(.*\)@@.*/\1() { print "\2"; }/'
+                ;;
+            *@@*::*@@*) # "complex" metadata: can be anything
+                print "$line" |
+                    sed 's/.*@@\([^:]*\):: \?\(.*\)@@.*/\1() { \2 ; }/'
+                ;;
+        esac >> "$HTENV"
+        # Still print the line to the body (no need to escape or w/e)
+        print "$line" >> "$HTBOD"
+    done
+    env | grep '^HT' | sort | uniq >> "$HTENV"
+}
+
+ht_main() { # main TEMPLATE < INPUT
+    ## Apply TEMPLATE to INPUT and print it.
+    # TEMPLATE will be interpreted as a heredoc.
+    if [ $# -eq 0 ]; then
+        print "ht.sh TEMPLATE < INPUT" >&2
+        exit 1
+    fi
+
+    eval "ht_build_env; . \"$HTENV\"; print \"\$(htt \"\$@\")\";";
+}
+
+# To keep this POSIX-compliant, we can't use a bashism like
+# [[ "$0" == # "$BASH_SOURCE[0]" ]].  However, there are still ways to guess
+# whether the user is sourcing this file as a library or executing it as a
+# script.
+
+case "$0" in
+    *ht.sh) ht_main "$@" ;;
+    *) print "Sourcing ht.sh" ;;
+esac