Syntax

  In MzScheme, syntactic forms (such as lambda or define) are handled by a binding global variable to a Scheme value representing a syntax resolver. MzScheme does not allow a variable that is bound to a syntax resolver to be used in a non-application position.

MzScheme can be extended with arbitrary syntactic forms. However, this is difficult, and it is rarely necessary. Most any functionality can be added to MzScheme by adding new primitive procedures (and perhaps some macros) instead.

A new syntax resolver is created by passing two function pointers to  scheme_make_compiled_syntax:

• The first function takes an S-expression and compiles it, returning a compiled Scheme expression. A compiled expression usually consists of a pair: a syntax evaluator function and the syntax data; this pair is combined using  make_syntax_compilation.
• The second function takes an S-expression and expands it into a new S-expression. Usually, expansion involves mapping  scmeme_expand over appropriate parts of the original expression.

Thus, extending MzScheme with new run-time syntax typically requires three functions: a compiler, an executor, and an expander. To support saving compiled code to a file, two additional functions may be necessary: a writer and reader for the compiler/executor syntax data.

• Compilier
  • Compilation Info
• Expander
• Examples
• Library Functions