Nim with macro

with.nim

import macros

proc replaceIdents(node: NimNode, name, to: string): NimNode =
    result = node
    for i in 0 ..< len(result):
        if result[i].kind == nnkIdent and eqIdent(result[i], name):
            result[i] = ident(to)
        else:
            result[i] = result[i].replaceIdents(name, to)

macro with(head: untyped, body: untyped): untyped =
    head.expectKind(nnkInfix)
    let name = head[2].strVal
    let to = head[1].strVal
    result = body.replaceIdents(name, to)

var x = 123

with x as y:
    echo y
    for i in 1 .. 5:
        echo y + i