New infix syntax

FC++ v1.5 offers a new infix syntax that can be used with full functoids. The syntax is inspired by the Haskell programming language.

Given a two-argument full functoid which can normally be called as

   f(x,y)

you can now (as of v1.5) call the functoid using infix syntax as

   x ^f^ y

We overload operator^ for full functoids to make this work. The goal is to write more readable code, as some named functions "read" best infix (rather than prefix). For example,

   plus(2,3)

is ok, but

   2 ^plus^ 3

reads more nicely.

(Note that this also works for 3-argument functoids using implicit currying. Here's an example using the 3-ary functoid foldl:

   plus ^foldl^ 0

means the same as

   foldl( plus, 0 )

which results in a function which sums the values in an integer list.)

For lambda expressions, we overload operator% so that instead of

   f[X,Y]

you can write

   X %f% Y

See the discussion about lambda for more details.

Important: note that infix functions adopt the precedence and associativity of their C++ operators. So unless you know C++ operator precedence and associativity rules very well, we recommend that you use parentheses:

   // desired: y+3*x   ( Note: equals  y+(3*x) )
   y ^plus^ (3 ^multiplies^ x)   // good
   // probably wrong:   y ^plus^ 3^multiplies^x

New infix syntax

Last updated on May 20, 2003 by Brian McNamara