- GPP is a programming language with lisp dialect, it uses prefix notation, and it has only fractional types.
- It supports: variables, assignment expressions, boolean expressions, arithmetic expressions, function definitions, function calls.
clisp gpp_interpreter
- The only type in the language is VALUEF.
- f is used as fraction. Integer and other types are not recognized by this language. Both sides of f are unsigned integers. Language does operations with using nominator denominator of fraction.
- set, and defvar used for assignment expression. Language uses symbol table for association.
- These three operations are supported by the language, it also supports nested operations. Result is simplified after the calculation. Expression returns simplified results. All these 3 operators, can take only 2 operand.
- Expression List requires a progn keyword to indicate if it is expression list or not. In this way it can be differentiated from function calls by the interpreter.
- If uses boolean expression for decision. Boolean expressions, returns invalid syntax when it is directly written to the interpreter without if expressions. Internally it uses true, and false keywords, true and false keywords are also a boolean expression. If expression can take single expression or expression list.
- Function def requires deffun keyword id, arglist, and explist. After the definition it is associated with the function table. Each function call creates a local stack, variables are different from global symbol table. Each function call uses its local symbol table as referencing enviroment for variables. They can call other functions.
