1.52 class eq

Binary_condition object that succeeds if eq<-left and eq<-right evaluate to the same numeric value. See class binary_condition for details.

Besides acting as a simple test, it can also solve equations with a single variable. See eq<-var.

See also

topic Conditions

1.52.1 Send methods

eq ->_execute:

Evaluate both expressions to a numeric value and succeed if they evaluate to the same value.

1.52.2 Get methods

eq <-var: ->

Regards the = object as an equation to be solved. It can determine the value of a variable occuring only once in the equation if all other variables are given. This facility is used by class spatial to express spatial relations between graphical objects. Below are some examples:

?- get(4+x=7, var, x, X)		==> X = 3
?- get(5*x=y, var, y, x=3, Y)	==> Y = 15

Note that x, y, w, h and some more are the names of predefined var objects and thus x is translated to this var object by PCE's type-checking system. The binding of the var objects in an = object are not affected by this method.

See also class var and class spatial.

See also

class spatial