@steveGit's version of LC in Red

.red

Red []

lc: function [rule] [
    parse rule [
        some [
            s: word! 'in skip
                (in: last reduce/into ['foreach s/1 s/3 make block! 4] in)
            | 'if skip
                (in: last reduce/into ['if to-paren s/2 make block! 4] in)
            | skip '|
                (res: s/1 fun: in: make block! 4)
            | (reduce/into ['reduce/into res 'tail 'out] in) break
        ]
    ]
    has [out] compose [out: make block! 10 (fun) out] 
]

x-set: [1 2 3]
r: lc [[x + y ] | x in x-set y in [10 100 1000] if [ x <> 2]]
print source r
print r