LOOPING CONSTRUCTS

BASIC LOOPING FORM

(loop <expr>...)

<expr> the body of the loop

returns never returns (must use non-local exit, such as RETURN)

GENERAL LOOPING FORM

(do (<binding>...) (<texpr> <rexpr>...) <expr>...)

(do* (<binding>...) (<texpr> <rexpr>...) <expr>...)

fsubr. do binds simultaneously, do* binds sequentially

<binding> the variable bindings each of which is either:

1) a symbol (which is initialized to NIL)
2) a list of the form: (<sym> <init> [<step>])

<sym> is the symbol to bind
<init> the initial value of the symbol
<step> a step expression

<texpr> the termination test expression

<rexpr> result expressions (the default is NIL)

<expr> the body of the loop (treated like an implicit prog)

returns the value of the last result expression

LOOP THROUGH A LIST

(dolist (<sym> <expr> [<rexpr>]) <expr>...)

<sym> the symbol to bind to each list element

<expr> the list expression

<rexpr> the result expression (the default is NIL)

<expr> the body of the loop (treated like an implicit prog)

returns the result expression

LOOP FROM ZERO TO N-1

(dotimes (<sym> <expr> [<rexpr>]) <expr>...)

<sym> the symbol to bind to each value from 0 to n-1

<expr> the number of times to loop

<rexpr> the result expression (the default is NIL)

<expr> the body of the loop (treated like an implicit prog)

returns the result expression

XLISP-PLUS - Version 2.1g - Tom Almy tom.almy@tek.com - 18 JUL 94

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