racket/collects/scribblings/reference/startup.scrbl

458 lines
20 KiB
Racket

#lang scribble/doc
@(require "mz.rkt" scribble/bnf (for-label racket/pretty racket/gui/base))
@(define (FlagFirst n) (as-index (Flag n)))
@(define (DFlagFirst n) (as-index (DFlag n)))
@(define (PFlagFirst n) (as-index (PFlag n)))
@(define (nontermstr s)
@elem{@racketvalfont{"}@nonterm[s]@racketvalfont{"}})
@(define eventspace
@tech[#:doc '(lib "scribblings/gui/gui.scrbl")]{eventspace})
@title[#:tag "running-sa"]{Running Racket or GRacket}
The core Racket run-time system is available in two main variants:
@itemize[
@item{Racket, which provides the primitives libraries on which
@racketmodname[racket/base] is implemented. On Unix and Mac
OS X, the executable is called
@as-index{@exec{racket}}. On Windows, the executable is
called @as-index{@exec{Racket.exe}}.}
@item{GRacket, which is a GUI variant of @exec{racket} to the degree
that the system distinguishes them. On Unix, the executable
is called @as-index{@exec{gracket}}, and single-instance flags
and X11-related flags are handled and communicated specially to
the @racket[racket/gui/base] library. On Windows, the
executable is called @as-index{@exec{GRacket.exe}}, and it is a
GUI application (as opposed to a console application) that
implements singe-instance support. On Mac OS X, the
@exec{gracket} script launches @as-index{@exec{GRacket.app}}.}
]
@; ----------------------------------------------------------------------
@section[#:tag "init-actions"]{Initialization}
On start-up, the top-level environment contains no bindings---not even
@racket[#%app] for function application. Primitive modules with names
that start with @racketidfont{#%} are defined, but they are not meant
for direct use, and the set of such modules can change. For example,
the @indexed-racket['#%kernel] module is eventually used to bootstrap
the implementation of @racketmodname[racket/base].
The first action of Racket or GRacket is to initialize
@racket[current-library-collection-paths] to the result of
@racket[(find-library-collection-paths _pre-extras _extras)], where
@racket[_pre-extras] is normally @racket[null] and @racket[_extras]
are extra directory paths provided in order in the command line with
@Flag{S}/@DFlag{search}. An executable created from the Racket or
GRacket executable can embed paths used as @racket[_pre-extras].
Racket and GRacket next @racket[require] @racketmodname[racket/init]
and @racketmodname[racket/gui/init], respectively, but only if the
command line does not specify a @racket[require] flag
(@Flag{t}/@DFlag{require}, @Flag{l}/@DFlag{lib}, or
@Flag{u}/@DFlag{require-script}) before any @racket[eval],
@racket[load], or read-eval-print-loop flag (@Flag{e}/@DFlag{eval},
@Flag{f}/@DFlag{load}, @Flag{r}/@DFlag{script}, @Flag{m}/@DFlag{main},
or @Flag{i}/@DFlag{repl}). The initialization library can be changed
with the @Flag{I} @tech{configuration option}. The
@racket['configure-runtime] property of the initialization library's
language is used before the library is instantiated; see
@secref["configure-runtime"].
After potentially loading the initialization module, expression
@racket[eval]s, files @racket[load]s, and module @racket[require]s are
executed in the order that they are provided on the command line. If
any raises an uncaught exception, then the remaining @racket[eval]s,
@racket[load]s, and @racket[require]s are skipped. If the first
@racket[require] precedes any @racket[eval] or @racket[load] so that
the initialization library is skipped, then the
@racket['configure-runtime] property of the required module's library
language is used before the module is instantiated; see
@secref["configure-runtime"].
After running all command-line expressions, files, and modules,
Racket or GRacket then starts a read-eval-print loop for interactive
evaluation if no command line flags are provided other than
@tech{configuration options}. If any command-line argument is
provided that is not a @tech{configuration option}, then the
read-eval-print-loop is not started, unless the @Flag{i}/@DFlag{repl}
flag is provided on the command line to
specifically re-enable it. In addition, just before the command line
is started, Racket loads the file @racket[(find-system-path
'init-file)] and GRacket loads the file
@racket[(find-graphical-system-path 'init-file)] is loaded, unless the
@Flag{q}/@DFlag{no-init-file} flag is specified on the command line.
Finally, before Racket or GRacket exits, it calls the procedure that
is the current value of @racket[executable-yield-handler] in the main
thread, unless the @Flag{V}/@DFlag{no-yield} command-line flag is
specified. Requiring @racketmodname[racket/gui/base] sets this parameter call
@racket[(racket 'yield)].
@; ----------------------------------------------------------------------
@section[#:tag "exit-status"]{Exit Status}
The default exit status for a Racket or GRacket process is non-zero if
an error occurs during a command-line @racket[eval] (via @Flag{e},
etc.), @racket[load] (via @Flag{f}, @Flag{r}, etc.), or
@racket[require] (via @Flag{-l}, @Flag{t}, etc.), but only when no
read-eval-print loop is started. Otherwise, the default exit status is
@racket[0].
In all cases, a call to @racket[exit] (when the default @tech{exit
handler} is in place) can end the process with a specific status
value.
@; ----------------------------------------------------------------------
@include-section["init.scrbl"]
@; ----------------------------------------------------------------------
@section[#:tag "mz-cmdline"]{Command Line}
The Racket and GRacket executables recognize the following command-line
flags:
@itemize[
@item{File and expression options:
@itemize[
@item{@FlagFirst{e} @nonterm{expr} or @DFlagFirst{eval}
@nonterm{expr} : @racket[eval]s @nonterm{expr}. The results of
the evaluation are printed via @racket[current-print].}
@item{@FlagFirst{f} @nonterm{file} or @DFlagFirst{load}
@nonterm{file} : @racket[load]s @nonterm{file}; if
@nonterm{file} is @filepath{-}, then expressions are read and
evaluated from standard input.}
@item{@FlagFirst{t} @nonterm{file} or @DFlagFirst{require}
@nonterm{file} : @racket[require]s @nonterm{file}, and then
@racket[require]s @racket[(submod (file @#,nontermstr{file})
main)] if available.}
@item{@FlagFirst{l} @nonterm{path} or @DFlagFirst{lib}
@nonterm{path} : @racket[require]s @racket[(lib
@#,nontermstr{path})], and then @racket[require]s
@racket[(submod (lib @#,nontermstr{path}) main)] if available.}
@item{@FlagFirst{p} @nonterm{package} :
@racket[require]s @racket[(planet @#,nontermstr{package})],
and then
@racket[require]s @racket[(submod (planet @#,nontermstr{package})
main)] if available.}
@item{@FlagFirst{r} @nonterm{file} or @DFlagFirst{script}
@nonterm{file} : @racket[load]s @nonterm{file}
@margin-note*{Despite its name, @DFlag{script} is not usually
used for Unix scripts. See @guidesecref["scripts"] for more
information on scripts.}
as a script. This flag is like @Flag{t} @nonterm{file} plus
@Flag{N} @nonterm{file} to set the program name and @Flag{-}
to cause all further command-line elements to be treated as
non-flag arguments.}
@item{@FlagFirst{u} @nonterm{file} or @DFlagFirst{require-script}
@nonterm{file} : @racket[require]s @nonterm{file} as a script;
This flag is like @Flag{t} @nonterm{file} plus @Flag{N}
@nonterm{file} to set the program name and @Flag{-} to cause
all further command-line elements to be treated as non-flag
arguments.}
@item{@FlagFirst{k} @nonterm{n} @nonterm{m} @nonterm{p} : Loads code
embedded in the executable from file position @nonterm{n} to
@nonterm{m} and from @nonterm{m} to @nonterm{p}. (On Mac OS X,
@nonterm{n}, @nonterm{m}, and @nonterm{p} are relative to a
@tt{__PLTSCHEME} segment in the executable.) The first range
is loaded in every new @tech{place}, and any modules declared
in that range are considered predefined in the sense of
@racket[module-predefined?]. This option is normally embedded
in a stand-alone binary that also embeds Racket code.}
@item{@FlagFirst{m} or @DFlagFirst{main} : Evaluates a call to
@racketidfont{main} as bound in the top-level environment. All
of the command-line arguments that are not processed as
options (i.e., the arguments put into
@racket[current-command-line-arguments]) are passed as
arguments to @racketidfont{main}. The results of the call are
printed via @racket[current-print].
The call to @racketidfont{main} is constructed as an
expression @racket[((unsyntax @racketidfont{main}) _arg-str
...)] where the lexical context of the expression gives
@racketidfont{#%app} and @racketidfont{#%datum} bindings as
@racket[#%plain-app] and @racket[#%datum], but the lexical
context of @racketidfont{main} is the top-level environment.}
]}
@item{Interaction options:
@itemize[
@item{@FlagFirst{i} or @DFlagFirst{repl} : Runs an interactive read-eval-print
loop, using either @racket[read-eval-print-loop] (Racket) or
@racket[graphical-read-eval-print-loop] (GRacket) after showing
@racket[(banner)] and loading @racket[(find-system-path
'init-file)]. For GRacket, supply the @Flag{z}/@DFlag{text-repl}
configuration option to use @racket[read-eval-print-loop]
instead of @racket[graphical-read-eval-print-loop].}
@item{@FlagFirst{n} or @DFlagFirst{no-lib} : Skips requiring the
initialization library (i.e., @racketmodname[racket/init] or
@racketmodname[racket/gui/init], unless it is changed with the
@Flag{I} flag) when not otherwise disabled.}
@item{@FlagFirst{v} or @DFlagFirst{version} : Shows
@racket[(banner)].}
@item{@FlagFirst{K} or @DFlagFirst{back} : GRacket, Mac OS X only;
leave application in the background.}
@item{@FlagFirst{V} @DFlagFirst{no-yield} : Skips final
@racket[executable-yield-handler] action, which normally waits until all
frames are closed, @|etc| in the main @|eventspace| before
exiting for programs that use @racketmodname[racket/gui/base].}
]}
@item{@deftech{Configuration options}:
@itemize[
@item{@FlagFirst{c} or @DFlagFirst{no-compiled} : Disables loading
of compiled byte-code @filepath{.zo} files, by initializing
@racket[current-compiled-file-paths] to @racket[null].
Use judiciously: this effectively ignores the content of all
@filepath{compiled} subdirectories, so that any used modules are
compiled on the fly---even @racketmodname[racket/base] and
its dependencies---which leads to prohibitively expensive
run times.}
@item{@FlagFirst{q} or @DFlagFirst{no-init-file} : Skips loading
@racket[(find-system-path 'init-file)] for
@Flag{i}/@DFlag{repl}.}
@item{@FlagFirst{z} or @DFlagFirst{text-repl} : GRacket only; changes
@Flag{i}/@DFlag{repl} to use
@racket[textual-read-eval-print-loop] instead of
@racket[graphical-read-eval-print-loop].}
@item{@FlagFirst{I} @nonterm{path} : Sets @racket[(lib
@#,nontermstr{path})] as the path to @racket[require] to initialize
the namespace, unless namespace initialization is disabled. Using
this flag can effectively set the language for the read-eval-print
loop and other top-level evaluation.}
@item{@FlagFirst{X} @nonterm{dir} or @DFlagFirst{collects}
@nonterm{dir} : Sets @nonterm{dir} as the path to the main
collection of libraries by making @racket[(find-system-path
'collects-dir)] produce @nonterm{dir}. If @nonterm{dir} is an
empty string, then @racket[(find-system-path 'collects-dir)]
returns @filepath{.}, but
@racket[current-library-collection-paths] is initialized to
the empty list and @racket[use-collection-link-paths] is
initialized to @racket[#f].}
@item{@FlagFirst{S} @nonterm{dir} or @DFlagFirst{search}
@nonterm{dir} : Adds @nonterm{dir} to the default library
collection search path after the main collection directory. If
the @Flag{S}/@DFlag{dir} flag is supplied multiple times, the
search order is as supplied.}
@item{@FlagFirst{R} @nonterm{paths} or @DFlagFirst{compiled}
@nonterm{paths} : Sets the initial value of the
@racket[current-compiled-file-roots] parameter, overriding
any @envvar{PLTCOMPILEDROOTS} setting. The @nonterm{paths}
argument is parsed in the same way as @envvar{PLTCOMPILEDROOTS}
(see @racket[current-compiled-file-roots]).}
@item{@FlagFirst{A} @nonterm{dir} or @DFlagFirst{addon}
@nonterm{dir} : Sets the directory that is returned by
@racket[(find-system-path 'addon-dir)].}
@item{@FlagFirst{C} @nonterm{file} or @DFlagFirst{links}
@nonterm{file} : Sets the user-specific @tech{collection links file} path
that is returned by @racket[(find-system-path 'links-file)];
see also @secref["links-file"].}
@item{@FlagFirst{U} or @DFlagFirst{no-user-path} : Omits
user-specific paths in the search for collections, C
libraries, etc. by initializing the
@racket[use-user-specific-search-paths] parameter to
@racket[#f].}
@item{@FlagFirst{N} @nonterm{file} or @DFlagFirst{name}
@nonterm{file} : sets the name of the executable as reported
by @racket[(find-system-path 'run-file)] to
@nonterm{file}.}
@item{@FlagFirst{J} @nonterm{name} or @DFlagFirst{wm-class}
@nonterm{name} : GRacket, Unix only; sets the @tt{WM_CLASS}
program class to @nonterm{name} (while the @tt{WM_CLASS}
program name is derived from the executable name or a
@Flag{N}/@DFlag{name} argument).}
@item{@FlagFirst{j} or @DFlagFirst{no-jit} : Disables the
native-code just-in-time compiler by setting the
@racket[eval-jit-enabled] parameter to @racket[#f].}
@item{@FlagFirst{d} or @DFlagFirst{no-delay} : Disables on-demand
parsing of compiled code and syntax objects by setting the
@racket[read-on-demand-source] parameter to @racket[#f].}
@item{@FlagFirst{b} or @DFlagFirst{binary} : Requests binary mode,
instead of text mode, for the process's input, out, and error
ports. This flag currently has no effect, because binary mode
is always used.}
@item{@FlagFirst{W} @nonterm{levels} or @DFlagFirst{warn}
@nonterm{levels} : Sets the logging level for writing events to
the original error port. The possible @nonterm{level} values
are the same as for the @envvar{PLTSTDERR} environment
variable. See @secref["logging"] for more information.}
@item{@FlagFirst{L} @nonterm{levels} or @DFlagFirst{syslog}
@nonterm{levels} : Sets the logging level for writing events to
the system log. The possible @nonterm{level} values
are the same as for the @envvar{PLTSYSLOG} environment
variable. See @secref["logging"] for more information.}
]}
@item{Meta options:
@itemize[
@item{@FlagFirst{-} : No argument following this flag is itself used
as a flag.}
@item{@FlagFirst{h} or @DFlagFirst{help} : Shows information about
the command-line flags and start-up process and exits,
ignoring all other flags.}
]}
]
If at least one command-line argument is provided, and if the first
one after any @tech{configuration option} is not a flag, then a
@Flag{u}/@DFlag{require-script} flag is implicitly added before the
first non-flag argument.
If no command-line arguments are supplied other than
@tech{configuration options}, then the @Flag{i}/@DFlag{repl} flag is
effectively added.
For GRacket on Unix, the follow flags are recognized when they appear
at the beginning of the command line, and they count as configuration
options (i.e., they do not disable the read-eval-print loop or prevent
the insertion of @Flag{u}/@DFlag{require-script}):
@itemize[
@item{@FlagFirst{display} @nonterm{display} : Sets the X11 display
to use.}
@item{@FlagFirst{geometry} @nonterm{arg}, @FlagFirst{bg}
@nonterm{arg}, @FlagFirst{background} @nonterm{arg},
@FlagFirst{fg} @nonterm{arg}, @FlagFirst{foreground}
@nonterm{arg}, @FlagFirst{fn} @nonterm{arg}, @FlagFirst{font}
@nonterm{arg}, @FlagFirst{iconic}, @FlagFirst{name}
@nonterm{arg}, @FlagFirst{rv}, @FlagFirst{reverse},
@PFlagFirst{rv}, @FlagFirst{selectionTimeout} @nonterm{arg},
@FlagFirst{synchronous}, @FlagFirst{title} @nonterm{arg},
@FlagFirst{xnllanguage} @nonterm{arg}, or @FlagFirst{xrm}
@nonterm{arg} : Standard X11 arguments that are mostly ignored
but accepted for compatibility with other X11 programs. The
@Flag{synchronous} flag behaves in the usual
way.}
@item{@FlagFirst{singleInstance} : If an existing GRacket is already
running on the same X11 display, if it was started on a
machine with the same hostname, and if it was started with the
same name as reported by @racket[(find-system-path
'run-file)]---possibly set with the @Flag{N}/@DFlag{name}
command-line argument---then all non-option command-line
arguments are treated as filenames and sent to the existing
GRacket instance via the application file handler (see
@racket[application-file-handler]).}
]
Similarly, on Mac OS X, a leading switch starting with
@FlagFirst{psn_} is treated as a special configuration option. It
indicates that Finder started the application, so the current input,
output, and error output are redirected to a GUI window.
Multiple single-letter switches (the ones preceded by a single
@litchar{-}) can be collapsed into a single switch by concatenating
the letters, as long as the first switch is not @Flag{-}. The
arguments for each switch are placed after the collapsed switches (in
the order of the switches). For example,
@commandline{-ifve @nonterm{file} @nonterm{expr}}
and
@commandline{-i -f @nonterm{file} -v -e @nonterm{expr}}
are equivalent. If a collapsed @Flag{-} appears before other collapsed
switches in the same collapsed set, it is implicitly moved to the end
of the collapsed set.
Extra arguments following the last option are available from the
@indexed-racket[current-command-line-arguments] parameter.
@; ----------------------------------------------------------------------
@section[#:tag "configure-runtime"]{Language Run-Time Configuration}
@guidealso["module-runtime-config"]
When a module is implemented using @hash-lang{}, the language after
@hash-lang{} can specify configuration actions to perform when a
module using the language is the main module of a program. The
language specifies run-time configuration by
@itemlist[
@item{attaching a @racket['module-language] @tech{syntax property} to
the module as read from its source (see @racket[module] and
@racket[module-compiled-language-info]);}
@item{having the function indicated by the @racket['module-language]
@tech{syntax property} recognize the
@indexed-racket['configure-runtime] key, for which it returns a list of
vectors; each vector must have the form @racket[(vector _mp
_name _val)] where @racket[_mp] is a @tech{module path},
@racket[_name] is a symbol, and @racket[_val] is an arbitrary
value; and}
@item{having each function called as @racket[((dynamic-require _mp
_name) _val)] configure the run-time environment, typically by
setting parameters such as @racket[current-print].}
]
A @racket['configure-runtime] query returns a list of vectors, instead
of directly configuring the environment, so that the indicated modules
to be bundled with a program when creating a stand-alone executable;
see @secref[#:doc raco-doc "exe"] in
@other-manual[raco-doc].
For information on defining a new @hash-lang[] language, see
@racketmodname[syntax/module-reader].