公式解析计算组件

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因为需要，在http://www.lazarus.freepascal.org/上查到的。组件网址http://artsoft.nm.ru/download.html

ArtFormula package contains two nonvisual Delphi and Lazarus componenst for symbolic expression parsing and evaluation. Provides runtime scripting engine for automating your programs.

Provides:

• 7 arithmetic operations
• 10 logical operations
• 6 bitwise operations
• string concatenation (@) and like (==) operator
• 24 arithmetic functions
• 10 statistical functions
• 2 logical functions
• 17 string functions
• 13 date functions
• 14 programming functions
• User defined constant
• User defined variables
• User defined functions (modules)
• Subroutines, global vars and constants
• Symbolical differentiation of functions with basic simplification of resulting derivatives
  

Arithmetic operation:
x + y, x - y, x * y, x / y, x % y (Mod), x ^ y (power), x\ y (Div)

Logical operation (true=1, false=0):
x > y, x < y, x >= y, x <= y, x = y, x <> y, ! x (not), x & y (and), x | y (or), x xor y

Bitwise operations:
x && y (band), x || y (bor), !!x (bnot), x bxor y, x >> y (shr), x << y (shl)

Predefined constants:
Pi = 3.1415926535897932385
True = 1
False = 0

Functions:
sin, cos, tan, sinh, cosh, tanh, asin, acos, atan, asinh, acosh, atanh, sqrt, exp, log, lg (log base 10), int (integer part of a number), frac (fractional part of a number), abs, sign, rnd, randomize, trunc (truncates value to a specified number of digits), round (rounds value to a specified number of digits)
max(x,y...), min(x,y,...), count(x,y,...), sum(x,y,...), sumofsquares(x,y,...), avg(x,y,...), variance(x,y,...), variancep(x,y,...), stddev(x,y,...), stddevp(x,y,...)
iff(cond,x,y) (if cond = true then result = x else result = y),
isnumber(x)
chr(x), length(s), trim(s), trimleft(s), trimright(s) lowercase(s), uppercase(s), midstr(s,x,y), leftstr(s,x), rightstr(s,x), pos(s,t), code(s), format(s,x), formatf(s,x), stringofchar(c,n), concat(s1,s2,...), hex(s)
date(s), now, formatdate(s,d), year(d), month(d), day(d), hour(d), minute(d), second(d), millisecond(d), isleapyear(n), dayofweek(d), encodedate(y,m,d)

Programming:

TArtFormula provides two styles of programming: formula style and scripting style. The first style assumes that all statements have the form of function call. The second style imply that you use common program language notation.

ejiemu

不错！