Roland Ver. 4.5 Informações Técnicas descarregar pdf (Página 144)

134 GNU make

character

A printable character is converted to the same character.

string A string containing only printable characters is converted to the same string.

list A list is converted recursively according to the above rules. This implies that

any structured list will be ﬂattened (that is, a result of ‘’(a b (c d) e)’ will be

converted to the make string ‘a b c d e’).

other Any other Guile type results in an error. In future versions of make, other Guile

types may be converted.

The translation of ‘#f’ (to the empty string) and ‘#t’ (to the non-empty string ‘#t’) is

designed to allow you to use Guile boolean results directly as make boolean conditions. For

example:

$(if $(guile (access? "myfile" R_OK)),$(info myfile exists))

As a consequence of these conversion rules you must consider the result of your Guile

script, as that result will be converted into a string and parsed by make. If there is no

natural result for the script (that is, the script exists solely for its side-eﬀects), you should

add ‘#f’ as the ﬁnal expression in order to avoid syntax errors in your makeﬁle.

12.1.2 Interfaces from Guile to make

In addition to the guile function available in makeﬁles, make exposes some procedures for

use in your Guile scripts. At startup make creates a new Guile module, gnu make, and

exports these procedures as public interfaces from that module:

gmk-expand

This procedure takes a single argument which is converted into a string. The

string is expanded by make using normal make expansion rules. The result of

the expansion is converted into a Guile string and provided as the result of the

procedure.

gmk-eval This procedure takes a single argument which is converted into a string. The

string is evaluated by make as if it were a makeﬁle. This is the same capability

available via the eval function (see Section 8.9 [Eval Function], page 93). The

result of the gmk-eval procedure is always the empty string.

Note that gmk-eval is not quite the same as using gmk-expand with the eval

function: in the latter case the evaluated string will be expanded twice; ﬁrst by

gmk-expand, then again by the eval function.

12.1.3 Example Using Guile in make

Here is a very simple example using GNU Guile to manage writing to a ﬁle. These Guile

procedures simply open a ﬁle, allow writing to the ﬁle (one string per line), and close the ﬁle.

Note that because we cannot store complex values such as Guile ports in make variables,

we’ll keep the port as a global variable in the Guile interpreter.

You can create Guile functions easily using define/endef to create a Guile script, then

use the guile function to internalize it:

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