Parser functions and operators

The following are the supported unary operators:


abs
sqrt
exp
ln
lg
ld
sin
cos
tan
cot
asin
acos
atan
acot
sinh
cosh
tanh
coth
asinh
acosh
atanh
acoth
floor
ceil
round
frac
int

The following binary operators are supported:


Precedence level 1:
   ^
   root
Precedence level 2:
   %
   mod
   div
Precedence level 3:
   *
   /
Precedence level 4:
   +
   -

The following constants are pre-defined:


pi = 3.14159265359
e = 2.71828182846

Last, but not least, there are the following types of parentheses:


opens as '(', closes as ')'
opens as '[', closes as ']'
opens as '{', closes as '}'