Change behavior. (require racket-makefile) and use (make <target>) instead of racket Makefile.rkt <target>

README.md

@@ -4,6 +4,9 @@
 Racket available and only adds targets, dependencies, timestamp based rebuilds,
 phony targets, external command execution and a few cleanup helpers.
 
+A makefile only defines its targets. Loading or running the file does not build
+anything by itself. Builds are started explicitly with `make`.
+
 ```racket
 #lang racket-makefile
 
@@ -26,6 +29,8 @@ phony targets, external command execution and a few cleanup helpers.
   (cleanup "scrbl" '("**.html" "**.js" "**.css")))
 ```
 
+## Installation
+
 Install a local checkout with:
 
 ```text
@@ -35,20 +40,68 @@ raco pkg install
 For a versioned archive, give the package name explicitly:
 
 ```text
-raco pkg install --name racket-makefile racket-makefile-0.1.1.zip
+raco pkg install --name racket-makefile racket-makefile-0.1.2.zip
 ```
 
-Run the default target or select one or more targets explicitly:
+## Running targets
+
+Load the makefile with `-t` and evaluate a `make` expression with `-e`:
 
 ```text
-racket Makefile.rkt
-racket Makefile.rkt clean
-racket Makefile.rkt clean all
+racket -t Makefile.rkt -e "(make)"
+racket -t Makefile.rkt -e "(make all)"
+racket -t Makefile.rkt -e "(make clean)"
+racket -t Makefile.rkt -e "(make clean all)"
 ```
 
-The language adds `target`, `deps`, `phony`, `default-target`, `run`, `rm-f`,
-`rm-rf`, `cleanup`, `$target`, `$deps` and `$<`. Dependency expressions may
-also produce lists, which are automatically flattened. Everything else is
+`(make)` uses the target selected with `default-target`. If no default target is
+specified, the first declared target is used.
+
+Loading the file alone only registers the targets:
+
+```text
+racket -t Makefile.rkt
+```
+
+No recipe is executed in that case.
+
+In DrRacket, open the makefile and press **Run**. This also only loads and
+registers the targets. Then use the Interactions window:
+
+```racket
+> (make)
+> (make clean)
+> (make all)
+> (make clean all)
+```
+
+Bare identifiers in `make` are target names, so no quote is needed. For
+example, `(make clean)` selects the target named `clean`.
+
+## Generated targets
+
+Because the rest of the language is ordinary Racket, targets can be generated
+with normal definitions and loops:
+
+```racket
+(define sources '("foo.c" "bar.c" "baz.c"))
+
+(define objects
+  (for/list ([src sources])
+    (define obj (path-replace-extension src #".o"))
+    (target obj
+      (deps src)
+      (run `(cc -c $< -o $target)))
+    obj))
+
+(target all
+  (deps objects))
+```
+
+Dependency expressions may produce lists; they are recursively flattened.
+
+The language adds `target`, `deps`, `phony`, `default-target`, `make`, `run`,
+`rm-f`, `rm-rf`, `cleanup`, `$target`, `$deps` and `$<`. Everything else is
 ordinary Racket.
 
 See the installed `racket-makefile` Scribble documentation for the full API.