Effect of types declaration on default values

Under GP, all GP variables start with a default value, which is 0 for local variables and 'v for gloval variable.

The gp2ccompiler follow this rule for variables declared without a type.

However, when a variable is declared with a type, gp2cwill not generate a default value are generated. This means that local(g) is equivalent to local(g:gen=0), but not to local(g:gen), and f(g)=... is equivalent to f(g:gen=0)=..., but not to f(g:gen)=....

This rule was decided for several reasons:

• The value 0 might not be an object suitable for the type in question. For example, local(v:vec) declare v as being of type vec. It make no sense to initialize v to 0 since 0 is not a valid vec object.

• This allows to define GP functions with mandatory arguments. This way, GP will issue an error if a mandatory argument is missing. Without this rule, there is no way to tell apart 0 and a missing argument.

• This allows to tell gp2cto not generated useless default values.