▼ |  | Syntax: Meta-Programming Helpers

1 | Syntax Object Helpers
2 | Module-Processing Helpers
3 | Macro Transformer Helpers
4 | Reader Helpers
5 | Non-Module Compilation And Expansion
6 | Trusting Standard Recertifying Transformers
7 | Attaching Documentation to Exports
8 | Parsing and specifying syntax
| Index

► | 2 | Module-Processing Helpers

2.1 | Reading Module Source Code
2.2 | Getting Module Compiled Code
2.3 | Resolving Module Paths to File Paths
2.4 | Simplifying Module Paths
2.5 | Inspecting Modules and Module Dependencies

On this page:

2.1`` Reading Module Source Code
with-module-reading-parameterization
check-module-form
2.2`` Getting Module Compiled Code
get-module-code
moddep-current-open-input-file
exn: get-module-code
2.3`` Resolving Module Paths to File Paths
resolve-module-path
resolve-module-path-index
2.4`` Simplifying Module Paths
collapse-module-path
collapse-module-path-index
2.5`` Inspecting Modules and Module Dependencies
show-import-tree

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### 2`` Module-Processing Helpers

#### 2.1`` Reading Module Source Code

( require syntax/modread )

( with-module-reading-parameterization thunk) → any
thunk : ( -> any )

Calls thunk with all reader parameters reset to their default values.

( check-module-form |  | stx |
|  | expected-module-sym |
|  | source-v) |

→ ( or/c syntax? false/c )
stx : ( or/c syntax? eof-object? )
expected-module-sym : symbol?
source-v : ( or/c string? false/c )

Inspects stx to check whether evaluating it will declare a module – at least if module is bound in the top-level to Racket’s module. The syntax object stx can contain a compiled expression. Also, stx can be an end-of-file, on the grounds that read-syntax can produce an end-of-file.

The expected-module-sym argument is currently ignored. In previous versions, the module form stx was obliged to declare a module who name matched expected-module-sym.

If stx can declare a module in an appropriate top-level, then the check-module-form procedure returns a syntax object that certainly will declare a module (adding explicit context to the leading module if necessary) in any top-level. Otherwise, if source-v is not #f, a suitable exception is raised using the write form of the source in the message; if source-v is #f, #f is returned.

If stx is eof or eof wrapped as a syntax object, then an error is raised or #f is returned.

#### 2.2`` Getting Module Compiled Code

( require syntax/modcode )

( get-module-code |  | module-path-v |  |  |  |
| [ | #:sub-path compiled-subdir0 |  |  |  |
|  | compiled-subdir |  |  |  |
|  | #:compile compile-proc0 |  |  |  |
|  | compile-proc |  |  |  |
|  | #:extension-handler ext-proc0 |  |  |  |
|  | ext-proc |  |  |  |
|  | #:choose choose-proc |  |  |  |
|  | #:notify notify-proc |  |  |  |
|  | #:source-reader read-syntax-proc]) |  | → |  | any

module-path-v : module-path?

| compiled-subdir0 |  | : |  | ( and/c path-string? relative-path? )
|  |  | = |  | "compiled"

| compiled-subdir |  | : |  | ( and/c path-string? relative-path? )
|  |  | = |  | compiled-subdir0

compile-proc0 : ( any/c . -> . any ) = compile
compile-proc : ( any/c . -> . any ) = compile-proc0
ext-proc0 : ( or/c false/c ( path? boolean? . -> . any )) = #f

| ext-proc |  | : |  | ( or/c false/c ( path? boolean? . -> . any ))
|  |  | = |  | ext-proc0

choose-proc

:

( path? path? path?
. -> .
( or/c ( symbols 'src 'zo 'so) false/c ))

|  |  | = |  | ( lambda (src zo so) #f)

notify-proc : ( any/c . -> . any ) = void

| read-syntax-proc |  | : |  | ( any/c input-port? . -> . syntax? )
|  |  | = |  | read-syntax

Returns a compiled expression for the declaration of the module specified by module-path-v.

The compiled-subdir argument defaults to "compiled"; it specifies the sub-directory to search for a compiled version of the module.

The compile-proc argument defaults to compile. This procedure is used to compile module source if an already-compiled version is not available.

The ext-proc argument defaults to #f. If it is not #f, it must be a procedure of two arguments that is called when a native-code version of path is should be used. In that case, the arguments to ext-proc are the path for the extension, and a boolean indicating whether the extension is a _loader file (#t) or not (#f).

The choose-proc argument is a procedure that takes three paths: a source path, a ".zo" file path, and an extension path (for a non-_loader extension). Some of the paths may not exist. The result should be either 'src, 'zo, 'so, or #f, indicating which variant should be used or (in the case of #f) that the default choice should be used.

The default choice is computed as follows: if a ".zo" version of path is available and newer than path itself (in one of the directories specified by compiled-subdir), then it is used instead of the source. Native-code versions of path are ignored, unless only a native-code non-_loader version exists (i.e., path itself does not exist). A _loader extension is selected a last resort.

If an extension is prefered or is the only file that exists, it is supplied to ext-proc when ext-proc is #f, or an exception is raised (to report that an extension file cannot be used) when ext-proc is #f.

If notify-proc is supplied, it is called for the file (source, ".zo" or extension) that is chosen.

If read-syntax-proc is provided, it is used to read the module from a source file (but not from a bytecode file).

( moddep-current-open-input-file )
→ ( path-string? . -> . input-port? )
( moddep-current-open-input-file proc) → void?
proc : ( path-string? . -> . input-port? )

A parameter whose value is used like open-input-file to read a module source or ".zo" file.

( struct |  | exn:get-module-code exn (path)
|  | #:extra-constructor-name make-exn:get-module-code )

path : path?

An exception structure type for exceptions raised by get-module-code.

#### 2.3`` Resolving Module Paths to File Paths

( require syntax/modresolve )

( resolve-module-path |  | module-path-v |  |  |  |
|  | rel-to-path-v) |  | → |  | path?

module-path-v : module-path?
rel-to-path-v : ( or/c path-string? ( -> any ) false/c )

Resolves a module path to filename path. The module path is resolved relative to rel-to-path-v if it is a path string (assumed to be for a file), to the directory result of calling the thunk if it is a thunk, or to the current directory otherwise.

( resolve-module-path-index |  | module-path-index |  |  |  |
|  | rel-to-path-v) |  | → |  | path?

module-path-index : module-path-index?
rel-to-path-v : ( or/c path-string? ( -> any ) false/c )

Like resolve-module-path but the input is a module path index; in this case, the rel-to-path-v base is used where the module path index contains the “self” index. If module-path-index depends on the “self” module path index, then an exception is raised unless rel-to-path-v is a path string.

#### 2.4`` Simplifying Module Paths

( require syntax/modcollapse )

( collapse-module-path |  | module-path-v |
|  | rel-to-module-path-v) |

→ ( or/c path? module-path? )
module-path-v : module-path?
rel-to-module-path-v : any/c

Returns a “simplified” module path by combining module-path-v with rel-to-module-path-v, where the latter must have the form '(lib ....) or a symbol, '(file <string>), '(planet ....), a path, or a thunk to generate one of those.

The result can be a path if module-path-v contains a path element that is needed for the result, or if rel-to-module-path-v is a non-string path that is needed for the result; otherwise, the result is a module path in the sense of module-path?.

When the result is a 'lib or 'planet module path, it is normalized so that equivalent module paths are represented by equal? results.

( collapse-module-path-index |  | module-path-index |
|  | rel-to-module-path-v) |

→ ( or/c path? module-path? )
module-path-index : module-path-index?
rel-to-module-path-v : any/c

Like collapse-module-path, but the input is a module path index; in this case, the rel-to-module-path-v base is used where the module path index contains the “self” index.

#### 2.5`` Inspecting Modules and Module Dependencies

( require syntax/moddep )

Re-exports syntax/modread, syntax/modcode, syntax/modcollapse, and syntax/modresolve, in addition to the following:

( show-import-tree module-path-v) → void?
module-path-v : module-path?

A debugging aid that prints the import hierarchy starting from a given module path.
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