functions.md

Functions

Functions declaring

To define a function, simply type <name>(<args>) = <expression>. For example: f(x,y)=x+y

Also, multi-lined functions are allowed. Rules of expression lines break:

• Expression is inside of parenthesis
• Or there is an operator in the end of previous line

For example:

f(x, y) = 
    a = x + y;
    println(a)

Or:

sum(mem) = reduce(
    (x, y) = x + y,
    mem
)

Multiple expressions in functions

Wait, what? You said function body is a single expression! Well, yes. The problem is function body is a single expression for interpreter. You, as human, can write multiple expressions in function body as well. For this, you need to separate them with semicolon. Result of the last one expression is function result For example:

f(x)=x+5;x

How do you think, what will f(1) return? Correct, value of x. x+5 does nothing, so result of this expression will be removed from the stack after semicolon

Higher-order functions

PyCalc supports even this. Higher-order function is a function that returns another function. For example:

f(a) = y(b) = a * b
mulBy5 = f(5)
mulBy5(5)

This example will return 25

Function calls

To call a function, simply type <name>(<args>). For example: root(25, 2)

Function may have [0, +∞) arguments, separated by comma. Function call has maximal priority (just like power)

Lambda

Lambda is simply function without name. It can be defined directly as an argument for some function. Or just be a value for some variable.

Semantic:

(x, y) = x + y

Example:

map((x)=x**2, range(0, 10))

Or even:

sqpow = (x)=x**2
sqpow(2)