# the little scheme

## Contents

## Introdcution

scheme, a dialect of lisp.

## Notes

The law of Car

The primitive`car`

is defined only for non-empty lists.The`cdr`

of any nonempty list is always another list.The law of Cons

The primitive`cons`

takes two arguments.The second arugument to`cons`

must be a list.The result is a list.The law of Null?

The primitive`null?`

is defined only for lists.The law of eq?

The primitive`eq?`

takes two arguments.Each must be a nonnumeric atom.The First Commandment

Always ask`null?`

as the first question in expressing any function.The Second Commandment

Use`cons`

to build lists.The Third Commandment

When building a list,describe the first typical element,and then cons it onto the natural recursion.The Fourth Commandment

Always change at least one argument while recurring.It must be changed to be closer to termination.The changing argument must be tested in the termination condition:when using cdr,test termination with`null?`

.The Fifth Commandment

When building a value with +,always use 0 for the value of the terminating line,for adding 0 does not change the value of an addition.

When building a value with x,always use 1 for the value of the terminating line,for multiplying by 1 doese not change the value of a multiplication.

When building a value with cons,always consider () for the value of the terminating line.

作者: hugozen

链接: http://hugozen.com/2012/12/02/2012-12-02-the-little-scheme/

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