nprocedure

nprocedure( 
s_funcName( 
s_formalArgument 
) 
g_expr1 ... 
)
=> s_funcName

Description

(SKILL mode only) Defines an nlambda function with a function name and a single formal argument. This is a syntax form that is not supported in SKILL++ mode.

The body of the procedure is a list of expressions to be evaluated one after another. The value of the last expression evaluated is returned as the value of the function. There must be no white space separating the s_funcName and the open parenthesis of the list containing s_formalArgument.

An nlambda function defined by nprocedure differs from a lambda function defined by procedure in that an nlambda function does not evaluate its arguments; it binds the whole argument list to its single formal argument. lambda functions, on the other hand, evaluate each argument in the argument list and bind them one by one to each formal argument on the formal argument list. It is recommended that procedure be used over nprocedure whenever possible, in part because procedure is faster and also offers better type checking.

In general, it is preferable to use lambda instead of nlambda because lambda is more efficient.

Arguments

s_funcName	Name of newly defined function.
s_formalArgument	Formal argument for the function definition.
g_expr1	SKILL expressions to be evaluated when the function is called.

Value Returned

s_funcName

Returns the name of the function defined.

Examples

Defines a lambda function.

procedure( printarg(x) println(x))
=> printarg

Defines an nlambda function.

nprocedure( nprintarg(x) println(x))
=> nprintarg

Calls a lambda function. Prints the value 20. println returns nil.y = 10
=> 10
printarg(y * 2)
20
=> nil

Calls an nlambda function. Prints a list of the unevaluated arguments. println returns nil.

nprintarg(y * 2)
((y * 2))
=> nil

Related Topics

Function and Program Structure

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