- [def] is used to define a variable (like before)
but if we assign a string such as [def var "string"] the string is evaluated to bool
in a different way: empty string is false, not empty string is true
- added [def?] statement - similar like [def] but define a variable only if such
a variable is not already defined
- added [let] statement - similar like [def] but with lazy evaluation (it is an alias to a function)
if it is called to assign a string e.g. [let var "string"] then this has the
same meaning like [def] - an alias is only created when we assign a function e.g. [let var my_function]
both [def] and [let] are using the same Vars object
- added [let?] - make an alias but only if such a variable is not already defined
- a std::map of variables moved outside of Generator
added method void SetVariables(Vars & variables);
- fixed: a result status was not correctly propagated when evaluating [def] statements,
this was in Call(...) function: last_res from variables was set in Find()
but later was overwritten by Call(...) called for parameters (recursively)
Tomasz Sowa