On this page:
1.1 Bytecode Files
1.2 Dependency Files
1.3 API for Making Bytecode
make-compilation-manager-load/ use-compiled-handler
1.4 API for Parallel-Build
1.5 Compilation Manager Hook for Syntax Transformers
1.6 Compiling to Raw Bytecode

1 raco make: Compiling Source to Bytecode

The raco make command accept filenames for Racket modules to be compiled to bytecode format. Modules are re-compiled only if the source Racket file is newer than the bytecode file and has a different SHA-1 hash, or if any imported module is recompiled or has a different SHA-1 hash for its compiled form plus dependencies.

1.1 Bytecode Files

A file "‹name›.‹ext›" is compiled to bytecode that is saved as "compiled/‹name›_‹ext›.zo" relative to the file. As a result, the bytecode file is normally used automatically when "‹name›.‹ext›" is required as a module, since the underlying load/use-compiled operation detects such a bytecode file.

For example, in a directory that contains the following files:


  raco make a.rkt

triggers the creation of "compiled/a_rkt.zo", "compiled/b_rkt.zo", and "compiled/c_rkt.zo". A subsequent

  racket a.rkt

loads bytecode from the generated ".zo" files, paying attention to the ".rkt" sources only to confirm that each ".zo" file has a later timestamp.

In contrast,

  racket b.rkt c.rkt

would create only "compiled/b_rkt.zo" and "compiled/c_rkt.zo", since neither "b.rkt" nor "c.rkt" imports "a.rkt".

1.2 Dependency Files

In addition to a bytecode file, raco make creates a file "compiled/‹name›_‹ext›.dep" that records dependencies of the compiled module on other module files and the source file’s SHA-1 hash. Using this dependency information, a re-compilation request via raco make can consult both the source file’s timestamp/hash and the timestamps/hashes for the bytecode of imported modules. Furthermore, imported modules are themselves compiled as necessary, including updating the bytecode and dependency files for the imported modules, transitively.

Continuing the raco make a.rkt example from the previous section, the raco make command creates "compiled/a_rkt.dep", "compiled/b_rkt.dep", and "compiled/c_rkt.dep" at the same time as the ".zo" files. The "compiled/a_rkt.dep" file records the dependency of "a.rkt" on "b.rkt", "c.rkt" and the racket library. If the "b.rkt" file is modified (so that its timestamp and SHA-1 hash changes), then running

  raco make a.rkt

again rebuilds "compiled/a_rkt.zo" and "compiled/b_rkt.zo".

For module files that are within library collections, raco setup uses the same ".zo" and ".dep" conventions and files as raco make, so the two tools can be used together.

1.3 API for Making Bytecode

The compiler/cm module implements the compilation and dependency management used by raco make and raco setup.

(make-compilation-manager-load/use-compiled-handler [delete-zos-when-rkt-file-does-not-exist?])
  (path? (or/c symbol? false/c) . -> . any)
  delete-zos-when-rkt-file-does-not-exist? : any/c = #f
Returns a procedure suitable as a value for the current-load/use-compiled parameter. The returned procedure passes it arguments on to the current-load/use-compiled procedure that is installed when make-compilation-manager-load/use-compiled-handler is called, but first it automatically compiles a source file to a ".zo" file if

If SHA-1 hashes override a timestamp-based decision to recompile the file, then the target ".zo" file’s timestamp is updated to the current time.

After the handler procedure compiles a ".zo" file, it creates a corresponding ".dep" file that lists the current version and the identification of every file that is directly required by the module in the compiled file. Additional dependencies can be installed during compilation via compiler/cm-accomplice. The ".dep" file also records the SHA-1 hash of the module’s source, and it records a combined SHA-1 hash of all of the dependencies that includes their recursive dependencies.

The handler caches timestamps when it checks ".dep" files, and the cache is maintained across calls to the same handler. The cache is not consulted to compare the immediate source file to its ".zo" file, which means that the caching behavior is consistent with the caching of the default module name resolver (see current-module-name-resolver).

If use-compiled-file-paths contains an empty list when make-compilation-manager-load/use-compiled-handler is called, then exn:fail:contract exception is raised.

If the delete-zos-when-rkt-file-does-not-exist? argument is a true value, then the returned handler will delete ".zo" files when there is no corresponding original source file.

Do not install the result of make-compilation-manager-load/use-compiled-handler when the current namespace contains already-loaded versions of modules that may need to be recompiled—unless the already-loaded modules are never referenced by not-yet-loaded modules. References to already-loaded modules may produce compiled files with inconsistent timestamps and/or ".dep" files with incorrect information.

(managed-compile-zo file [read-src-syntax])  void?
  file : path-string?
  read-src-syntax : (any/c input-port? . -> . syntax?)
   = read-syntax
Compiles the given module source file to a ".zo", installing a compilation-manager handler while the file is compiled (so that required modules are also compiled), and creating a ".dep" file to record the timestamps of immediate files used to compile the source (i.e., files required in the source).

If file is compiled from source, then read-src-syntax is used in the same way as read-syntax to read the source module. The normal read-syntax is used for any required files, however.

(trust-existing-zos)  boolean?
(trust-existing-zos trust?)  void?
  trust? : any/c
A parameter that is intended for use by setup-plt when installing with pre-built ".zo" files. It causes a compilation-manager load/use-compiled handler to “touch” out-of-date ".zo" files instead of re-compiling from source.

(make-caching-managed-compile-zo read-src-syntax)
  (path-string? . -> . void?)
  read-src-syntax : (any/c input-port? . -> . syntax?)
Returns a procedure that behaves like managed-compile-zo (providing the same read-src-syntax each time), but a cache of timestamp information is preserved across calls to the procedure.

(manager-compile-notify-handler)  (path? . -> . any)
(manager-compile-notify-handler notify)  void?
  notify : (path? . -> . any)
A parameter for a procedure of one argument that is called whenever a compilation starts. The argument to the procedure is the file’s path.

(manager-trace-handler)  (string? . -> . any)
(manager-trace-handler notify)  void?
  notify : (string? . -> . any)
A parameter for a procedure of one argument that is called to report compilation-manager actions, such as checking a file. The argument to the procedure is a string.

  (-> path? (or/c (cons/c number? promise?) #f))
(manager-skip-file-handler proc)  void?
  proc : (-> path? (or/c (cons/c number? promise?) #f))
A parameter whose value is called for each file that is loaded and needs recompilation. If the procedure returns a pair, then the file is skipped (i.e., not compiled); the number in the pair is used as the timestamp for the file’s bytecode, and the promise may be forced to obtain a string that is used as hash of the compiled file plus its dependencies. If the procedure returns #f, then the file is compiled as usual. The default is (lambda (x) #f).

(file-stamp-in-collection p)
  (or/c (cons/c number? promise?) #f)
  p : path?

(file-stamp-in-paths p paths)
  (or/c (cons/c number? promise?) #f)
  p : path?
  paths : (listof path?)
Returns the file-modification date and delayed hash of por its bytecode form (i.e., ".zo" file), whichever exists and is newer, if p is an extension of any path in paths (i.e., exists in the directory, a subdirectory, etc.). Otherwise, the result is #f.

This function is intended for use with manager-skip-file-handler.

(get-file-sha1 p)  (or/c string? #f)
  p : path?
Computes a SHA-1 hash for the file p; the result is #f if p cannot be opened.

(get-compiled-file-sha1 p)  (or/c string? #f)
  p : path?
Computes a SHA-1 hash for the bytecode file p, appending any dependency-describing hash available from a ".dep" file when available (i.e., the suffix on p is replaced by ".dep" to locate dependency information). The result is #f if p cannot be opened.

(with-compile-output p proc)  any
  p : path-string?
  proc : ([port input-port?] [tmp-path path?]  . -> . any)
Opens a temporary path for writing and calls proc passing the resulting port and tmp-path. Once proc returns, with-compile-output renames tmp-path to p and arranges to delete temp-path if there’s an exception. Breaks are managed so that the port is reliably closed and the tmp-path file is reliably deleted if there’s a break. The result of proc is the result of the with-compile-output call.

Windows prevents programs from overwriting files that are open. As a result, with-compile-output calls to rename-file-or-directory will fail if the destination file argument is an open file. Windows, however, does allow you to rename an open file. To avoid overwriting open files windows, with-compile-output creates a second temporary file tmp-path2, renames p to tmp-path2, renames tmp-path to p, and finally deletes tmp-path2.

  ([command (or/c 'lock 'unlock)] [zo-path bytes?] . -> . boolean?)
(parallel-lock-client proc)  void?
  proc : ([command (or/c 'lock 'unlock)] [zo-path bytes?] . -> . boolean?)
Holds the parallel compilation lock client, which prevents compilation races between parallel builders. The proc function takes a command argument of either 'lock or 'unlock. The zo-path argument specifies the path of the zo for which compilation should be locked.

When the proc 'lock command returns #t, the current builder has obtained the lock for zo-path. Once compilation of zo-path is complete, the builder process must release the lock by calling proc 'unlock with the exact same zo-path.

When the proc 'lock command returns #f, another parallel builder obtained the lock first and has already compiled the zo. The parallel builder should continue without compiling zo-path.


> (let* ([lc (parallel-lock-client)]
         [zo-name  #"collects/racket/compiled/draw_rkt.zo"]
         [locked? (and lc (lc 'lock zo-name))]
         [ok-to-compile? (or (not lc) locked?)])
      (lambda () (void))
      (lambda ()
        (when ok-to-compile?
          (printf "Do compile here ...\n")))
      (lambda ()
       (when locked?
         (lc 'unlock zo-name)))))

Do compile here ...

1.4 API for Parallel-Build

The setup/parallel-build library provides the parallel compilation to bytecode functionality of rack setup and raco make.

(parallel-compile-files list-of-files    
  [#:worker-count worker-count    
  #:handler handler])  void?
  list-of-files : (listof path?)
  worker-count : non-negative-integer? = (processor-count)
  handler : 
(->i ([handler-type symbol?]
      [path path-string?]
      [msg string?]
      [out string?]
      [err string?])
 = void
The parallel-compile utility function is used by raco make to compile a list of paths in parallel. The optional keyword argument #:worker-count specifies the number of compile workers to spawn during parallel compilation. The callback, handler, is called with the symbol 'done as the handler-type argument for each successfully compiled file, 'output when a successful compilation produces stdout/stderr output, 'error when a compilation error has occured, or 'fatal-error when a unrecoverable error occurs. The other arguments give more information for each status update.

  #:worker-count 4
  #:handler (lambda (type work msg out err)
    (match type
      ['done (when (verbose) (printf " Made ~a\n" work))]
      ['output (printf " Output from: ~a\n~a~a" work out err)]
      [else (printf " Error compiling ~a\n~a\n~a~a"

(parallel-compile worker-count    
  collects-tree)  (void)
  worker-count : non-negative-integer?
  setup-fprintf : 
(->* ([stage string?] [format string?])
     #:rest (listof any/c) void)
  append-error : (cc? [prefix string?] [exn (or/c exn? null?)] [out string?] [err srtring?] [message string?] . -> . void?)
  collects-tree : (listof any/c)
The parallel-compile internal utility function is used by rack setup to compile collects in parallel. The worker-count argument specifies the number of compile workers to spawn during parallel compilation. The setup-fprintf and append-error functions are internal callback mechanisms that rack setup uses to communicate intermediate compilation results. The collects-tree argument is a compound datastructure containing an in-memory tree representation of the collects directory.

1.5 Compilation Manager Hook for Syntax Transformers

 (require compiler/cm-accomplice)

(register-external-file file)  void?
  file : (and path? complete-path?)
Logs a message (see log-message) at level 'info. The message data is a file-dependency prefab structure type with one field whose value is file.

A compilation manager implemented by compiler/cm looks for such messages to register an external dependency. The compilation manager records (in a ".dep" file) the path as contributing to the implementation of the module currently being compiled. Afterward, if the registered file is modified, the compilation manager will know to recompile the module.

The include macro, for example, calls this procedure with the path of an included file as it expands an include form.

1.6 Compiling to Raw Bytecode

The --no-deps mode for raco make is an improverished form of the compilation, because it does not track import dependencies. It does, however, support compilation of non-module source in an namespace that initially imports scheme.

Outside of a module, top-level define-syntaxes, module, #%require, define-values-for-syntax, and begin expressions are handled specially by raco make --no-deps: the compile-time portion of the expression is evaluated, because it might affect later expressions.

For example, when compiling the file containing

(require racket/class)
(define f (class object% (super-new)))

the class form from the racket/class library must be bound in the compilation namespace at compile time. Thus, the require expression is both compiled (to appear in the output code) and evaluated (for further computation).

Many definition forms expand to define-syntaxes. For example, define-signature expands to define-syntaxes. In --no-deps mode, raco make --no-deps detects define-syntaxes and other expressions after expansion, so top-level define-signature expressions affect the compilation of later expressions, as a programmer would expect.

In contrast, a load or eval expression in a source file is compiled—but not evaluated!as the source file is compiled. Even if the load expression loads syntax or signature definitions, these will not be loaded as the file is compiled. The same is true of application expressions that affect the reader, such as (read-case-sensitive #t). The -p or --prefix flag for raco make takes a file and loads it before compiling the source files specified on the command line.

In general, a better solution is to put all code to compile into a module and use raco make in its default mode.