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_S_c_r_i_p_t_s
In Miranda the script is the persistent entity that is saved from
session to session (i.e. it plays the role of what is called a program
in conventional languages). Associated with a Miranda session at any
given time is a single current script, identified by a UNIX pathname
ending in `.m'.
A script is a collection of declarations, establishing an environment in
which you wish to evaluate expressions. The order of the declarations
in a script is not significant - for example there is no requirement
that an identifier be defined before it is used.
An identifier may not have more than one top-level binding in a given
script.
Here are the kinds of declaration that can occur in a script:
1) a definition (of a function, data structure etc. - see manual entry
`definitions' for more details). Example
fac n = product[1..n]
2) a specification of the type of one or more identifiers, of the form
var-list :: <type>
Example
fac :: num->num
See 'Basic type structure' for an account of possible types. Note that
these type specifications are normally optional, since the compiler is
able to deduce them from the definitions of the corresponding
identifiers. It is however possible to introduce an identifier by means
of a type specification only, without giving it a defining equation
(such identifiers are said to be `specified but not defined' and are
useful in program development). A special case of this is the
introduction of an otherwise undefined typename - see separate manual
entry on `placeholder types'.
3) the definition of a user defined type - these are of three kinds,
synonyms, algebraic types, and abstract types (see separate manual entry
on each).
4) a library directive (%export, %include or %free) these are used
specify the interfaces between separately compiled scripts - see
separate manual entry on the library mechanism.
There is a manual entry giving the formal syntax of Miranda scripts.
_N_o_t_e
A directory called `ex' (meaning `examples') containing a collection of
example scripts is supplied with the Miranda system, and will be found
under the `miralib' directory (usually kept at /usr/lib/miralib - the
Miranda session command `/miralib' will tell you where it is on your
system).
A convention which the Miranda system consistently understands in
Miranda session commands, library directives etc. is that a pathname
enclosed in <angle_brackets>, instead of "string_quotes" is relative to
the miralib directory. In particular note that the Miranda session
command
/cd <ex>
will change your current directory to be "..../miralib/ex". You can
then say, e.g.
!ls
to see what's in there. In fact there is a README file, so a good thing
to say next would be
!vi README
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