1 files changed, 56 insertions, 46 deletions

diff --git a/ship/build b/ship/build
index 486f4bed..10fc4345 100755
--- a/ship/build
+++ b/ship/build
@@ -5,6 +5,14 @@ set -euf
 # [debug=true] build compile SRCFILE DSTFILE
 # [debug=true] build deps SRCFILE...
 build() {
+
+  # usage_pattern is used to extract build directive declarations.
+  usage_pattern='## usage: \(.*\) -> \([^ ]\+\) \(.*\)'
+
+  script='s/^'"$usage_pattern"'$/\2_directive='"'"'\1'"'"'/p' \
+    setf build_x_directive_loader '$(sed -n "$script" "$%s")' 0
+  eval "$build_x_directive_loader"
+
   case "$1" in
     compile) build_compile "$2" "$3";;
     deps) shift; build_deps "$@";;
@@ -12,28 +20,7 @@ build() {
   esac
 }
 
-# usage: debug_script VARNAME [DESCRIPTION]
-debug_script() {
-  if test "${debug-false}" = true; then
-    printf '====== %s%s\n%s\n' \
-        "$1" \
-        "${2+" ($2)"}" \
-        "$(eval echo \"\$$1\" | nl -b a)" >&2
-  fi
-}
-
-## build directives
-build_info_directive='#@info'
-build_include_directive='#@include \([0-9A-Za-z]\+\)'
-
-input_parser="\
-s:^ *\([0-9]\+\) "$build_info_directive"$:build_info \1:
-s:^ *\([0-9]\+\) "$build_include_directive"$:build_include \1 \2:
-t
-s:^ *\([0-9]\+\) .*:echo \1p:"
-debug_script input_parser
-
-## usage: build_include LINENO LIBNAME
+## usage: #@include \([0-9A-Za-z]\+\) -> build_include \1 \2
 build_include() { cat<<EOF
 $1a\\
 # begin $2
@@ -43,7 +30,7 @@ $1a\\
 EOF
 }
 
-## usage: build_info LINENO
+## usage: #@info -> build_info \1
 build_info() { cat<<EOF
 $1a\\
 # this file was generated by //ship/build\\
@@ -54,37 +41,36 @@ EOF
 
 ## usage: build_compile SRCFILE DSTFILE
 build_compile() {
-  srcfile="$(cat "$1")"
-  debug_script srcfile 'SRCFILE'
 
-  while needs_compilation "$srcfile"; do
-    script="$(make_sedscript_maker_shellscript "$srcfile")"
-    srcfile="$(echo "$srcfile" | sed -n "$script")"
-    debug_script srcfile 'sed sedscript srcfile'
+  script='s/^'"$usage_pattern"'$/\2_directive/p' \
+    setf build_directives '$(sed -n "$script" "$%s")' 0
+
+  script='
+      s/^'"$usage_pattern"'$/s:^ *\\([0-9]\\+\\) \1$:\2 \3:/p
+      $a\
+      t\
+      s:^ *\\([0-9]\\+\\) .*:echo \\1p:
+      ' \
+    setf input_parser '$(sed -n "$script" "$%s")' 0
+
+  setf incomplete_pattern '$(make_incomplete_pattern $%s)' build_directives
+
+  SRCFILE="$1" setf src '$(cat "$%s")' SRCFILE
+
+  while needs_compilation "$src" "$incomplete_pattern"; do
+    setf sedgen '$(echo "$%s" | nl -b a -s \  | sed "$%s")' src input_parser
+    setf sedscript '$(eval "$%s")' sedgen
+    setf src '$(echo "$%s" | sed -n "$%s")' src sedscript
   done
 
-  echo "$srcfile" > "$2"
+  echo "$src" > "$2"
   chmod +x "$2"
 }
 
-## usage: needs_compilation SHELLSCRIPT
+## usage: needs_compilation SHELLSCRIPT PATTERN
 # Returns true if SRCFILE contains compilation directives.
 needs_compilation() {
-  echo "$1" |
-      grep -q "^\\($build_include_directive\\|$build_info_directive\\)$"
-}
-
-## usage: make_sedscript_maker_shellscript SRCFILE
-# Print a shellscript that creates a sedscript that resolves all the build
-# directives in SRCFILE.
-make_sedscript_maker_shellscript() {
-  sedscript_generator="$(echo "$1" | nl -b a -s ' ' | sed "$input_parser")"
-  debug_script sedscript_generator 'sed input_parser srcfile'
-
-  sedscript="$(eval "$sedscript_generator")"
-  debug_script sedscript 'eval sedscript_generator'
-
-  echo "$sedscript"
+  echo "$1" | grep -q "$2"
 }
 
 ## usage: build_deps SRCFILE...
@@ -118,4 +104,28 @@ build_resolve() {
   }
 }
 
+## usage: make_incomplete_pattern BUILD_DIRECTIVES...
+make_incomplete_pattern() {
+  echo "^\\($(
+    for directive; do
+      eval echo \"\$$directive\"
+    done |
+      tr \\n \| |
+      sed 's/|/\\|/'
+  )\\)$"
+}
+
+## usage: setf NAME FMT [ARG...]
+setf() {
+  value_script="$(shift; printf "$@")"
+
+  eval "$1=$value_script"
+
+  if test "${debug-false}" = true; then
+    eval 'echo "$1=\"$value_script\""'
+    eval 'echo "'"\$$1"'"' | nl -b a
+  fi >&2
+}
+
+## main
 build "$@"