evaluator.txt

pic 模拟程序！面向对象

evaluator.txt: This file documents the existing operators and
functions understood by the equation evaluator.

Operators:

= equality
- subtraction
+ addition
* multiplication
/ division
NEG negation (unary minus)
^ exponentiation

Functions:

sin(): sine of argument
cos(): cosine of argument
atan(): arctangent of argument
ln(): natural logarithm of argument
exp(): natural exponential of argument
sqrt(): square root of argument
pow(x,y): x^y
pulse(t,tdelay,trise,tpulse,tfall)   : finite pulse, see timefunc.txt 
step(x)	:  returns 0 if x < 0 and returns 1 otherwise
ramp(x) :  returns 0 if x < 0 and returns x otherwise

Constants:

PI = 3.141592654
e = 2.18281828