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_C_o_m_p_i_l_e_r_ _d_i_r_e_c_t_i_v_e_s
Certain keywords, beginning with `%', modify the action of the compiler
when present in a script. These are called `compiler directives'. The
directives currently available are as follows.
%list %nolist
If the `/list' feature is enabled (switched on and off by /list,
/nolist at command level) the compiler echos the source to the user's
terminal during compilation of a Miranda script. The directives %list,
%nolist may be placed in a file to give more detailed control over this
behaviour. If the compiler is in an echoing state then encountering
`%nolist' causes it to cease echoing from that point onwards in the
source, until the next occurrence of '%list' or the end of the source
file in which the directive occurs, whichever is the sooner. These
directives may occur anywhere in a script and have no effect on the
semantics (i.e. they are just like comments, apart from having a
side-effect on the lex analyser).
If the `/list' feature of the compiler is not enabled these directives
are ignored. Since the default state of the compiler is now `/nolist'
these directives are of marginal value and retained only for historical
reasons.
%insert
A directive of the form
%insert "pathname"
may occur anywhere in a Miranda script, and is textually replaced by the
contents of the file "pathname" during lexical analysis. The pathname
must be given as a literal string, enclosed in double quotes. (Most
uses of this directive are now better handled by %include, see below).
If the %insert directive is textually indented in the file in which it
occurs, the whole of the inserted text will be treated as being indented
by the same amount as the initial `%' of the directive.
Insert directives may be invoked recursively, to a depth limit imposed
by the operating system, typically about 16, which should be enough for
any reasonable purpose. Note that the pathnames are resolved
statically, not dynamically, so that the meaning of an _%_i_n_s_e_r_t directive
is computed relative to the file in which it occurs, NOT relative to the
directory from which the compiler was invoked.
The use of static rather than dynamic pathname resolution is a departure
from normal UNIX conventions (both the `C' compiler and the UNIX shell
resolve pathnames dynamically) but is much more convenient in practice.
Note that if the subject of an %insert directive is a complete Miranda
script it is always better to use %include (see manual section on the
library mechanism), since this avoids needless recompilation of the
definitions of the subsidiary script. The use of %include also imposes
a hierarchical scope discipline, and is more likely to lead to well
structured code.
A point to beware of when using %insert is that unlike %include, it does
NOT add a missing `.m' extension to its pathname argument automatically.
This is because the argument file may contain an arbitrary piece of text
(e.g. an expression or a signature) and need not be a complete Miranda
script, so it would be inappropriate to insist that it's pathname end in
`.m' in all cases.
%include %export %free
These directives control the identifier bindings between separately
compiled scripts. See separate manual entry on `the library mechanism'
for details.
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