What are the two types of macros?

Types of macros

• Executive macros.
• Declarative macros.

What is begin in scheme?

Scheme begin expressions aren’t just code blocks, though, because they are expressions that return a value. A begin returns the value of the last expression in the sequence. For example, the begin expression above returns the value returned by the call to bar . The bodies of procedures work like begin s as well.

What is macro definition and macro expansion?

Macro represents a group of commonly used statements in the source programming language. Macro Processor replaces each macro instruction with the corresponding group of source language statements. This is known as the expansion of macros.

Are there any examples of macro programming in scheme?

Scheme Macro Programming Articles and examples of macro programming in Scheme, using low-level (a.k.a., defmacro) and R5RS (hygienic) macro systems. previous next contents top

How does a Ck-macro work in scheme?

All arguments of a CK-macro except for sare always values; the macro is free to pattern-match on them. A CK-macro always expands into the call to the macro ck, passing it the sargument followed by the produced value or by the expression that will produce the resulting value. The macro c-consproduces a value, which is therefore quoted.

How to do a macro expansion in scheme?

The Scheme expression (ck () (c-append ‘(1 2 3) ‘(4 5)))will hopefully macro-expands to (1 2 3 4 5), which the Scheme expression evaluator will try to evaluate, reporting the error since 1 is not a procedure. To see the result of just the macro-expansion, without any further evaluations, we should quote it:

How are macros used in a programming language?

In computer programming, macros are a tool that allows a developer to re-use code. For instance, in the C programming language, this is an example of a simple macro definition which incorporates arguments: After being defined like this, our macro can be used in the code body to find the square of a number. See More….