Stellar Language Lambda Expressions

Stellar provides the capability to pass lambda expressions to functions which wish to support that layer of indirection. The syntax is:

(named_variables) -> stellar_expression : Lambda expression with named variables
For instance, the lambda expression which calls TO_UPPER on a named argument x could be expressed as (x) -> TO_UPPER(x).
var -> stellar_expression : Lambda expression with a single named variable, var
- For instance, the lambda expression which calls TO_UPPER on a named argument x could be expressed as x -> TO_UPPER(x). Note, this is more succinct but equivalent to the example directly above.
() -> stellar_expression : Lambda expression with no named variables.
- If no named variables are needed, you may omit the named variable section. For instance, the lambda expression which returns a constant false would be () -> false

where

named_variables is a comma separated list of variables to use in the Stellar expression
stellar_expression is an arbitrary stellar expression

In the core language functions, we support basic functional programming primitives such as

MAP - Applies a lambda expression over a list of input. For instance MAP([ 'foo', 'bar'], (x) -> TO_UPPER(x) ) returns [ 'FOO', 'BAR' ]
FILTER - Filters a list by a predicate in the form of a lambda expression. For instance FILTER([ 'foo', 'bar'], (x ) -> x == 'foo' ) returns [ 'foo' ]
REDUCE - Applies a function over a list of input. For instance REDUCE([ 1, 2, 3], (sum, x) -> sum + x, 0 ) returns 6

	Important
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​Stellar Language Lambda Expressions