Introduction

A comment is a part of the source file that is ignored by the compiler. It is usually used to explain what the program is supposed to do. Either single line comments or multi lines comments can be used in a source file. For the first case, the comment starts with the '!' character and terminates with the end of the line. A multi-line commentary must be inclosed in '(!' and '!)'. Note that it is possible to nest several multi-line commentaries.

! In a comment
 This text will be analyzed
 (! Start of a multi line
   (! Another comment
   blabla
   end of the second level comment !)
 end of the first level !) Analysis continues here 

Comments may appear anywhere in the source file.

Identifiers

Identifiers are used to name objects (variables, for instance). An identifier is an alphanumeric (plus '_') character string starting with an alphabetic character or '_'. All characters of an identifier are significant and the case is important (the identifier 'word' is not equivalent to 'Word').

Reserved words

The reserved words are identifiers with a particular meaning that determine a specific behaviour within the language. Because of their special role, these keywords cannot be used to name user defined objects (i.e. they cannot be redefined). The list of reserved words is:

and, array, as, boolean, break, case, constant, count, counter, declarations, div, do, dynamic, elif, else, end, evaluation, false, forall, forward, from, function, hashmap, if, imports, in, include, initialisations, initializations, integer, inter, is, is_binary, is_continuous,
is_free, is_integer, is_partint, is_semcont, is_semint, is_sos1, is_sos2, linctr, list, max, min, mod, model, mpvar, namespace, next, not, nsgroup, nssearch, of, options, or, package, parameters, procedure, public, prod, range, real, record, repeat, requirements, return, set, shared, string, sum, then, to, true, union, until, uses, version, while, with.

Note that, although the lexical analyzer of Mosel is case-sensitive, the reserved words are defined both as lower and upper case (i.e. AND and and are keywords but not And).

Separation of instructions, line breaking

In order to improve the readability of the source code, each statement may be split across several lines and indented using as many spaces or tabulations as required. However, as the line breaking is the expression terminator, if an expression is to be split, it must be cut after a symbol that implies a continuation like an operator ('+', '-', ...) or a comma (',') in order to warn the analyzer that the expression continues in the following line(s).

 A+B       ! Expression 1
 -C+D      ! Expression 2
 A+B-      ! Expression 3...
 C+D       ! ...end of expression 3 

Moreover, the character ';' can be used as an expression terminator.

 A+B ; -C+D  ! 2 expressions on the same line

Some users prefer to explicitly mark the end of each expression with a particular symbol. This is possible using the option explterm (see Section The compiler directives) which disables the default behaviour of the compiler. In that case, the line breaking is not considered any more as an expression separator and each statement finishing with an expression must be terminated by the symbol ';'.

 A+B;      ! Expression 1
 -C+D;     ! Expression 2
 A+B       ! Expression 3...
 -C+D;     ! ...end of expression 3 

Conventions in this document

In the following sections, the language syntax is explained. In all code templates, the following conventions are employed:

• word: 'word' is a keyword and should be typed as is;
• todo: 'todo' is to be replaced by something else that is explained later;
• [ something ]: 'something' is optional and the entire block of instructions may be omitted;
• [ something ...]: 'something' is optional but if used, it can be repeated several times.