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discard """
output: '''0 1
1 2
2 3
0 1
1 2
2 3
0 1
1 2
2 3
3 5'''
"""
import macros
{.experimental: "forLoopMacros".}
macro mymacro(): untyped =
result = newLit([1, 2, 3])
for a, b in mymacro():
echo a, " ", b
macro enumerate(x: ForLoopStmt): untyped =
expectKind x, nnkForStmt
# we strip off the first for loop variable and use
# it as an integer counter:
result = newStmtList()
result.add newVarStmt(x[0], newLit(0))
var body = x[^1]
if body.kind != nnkStmtList:
body = newTree(nnkStmtList, body)
body.add newCall(bindSym"inc", x[0])
var newFor = newTree(nnkForStmt)
for i in 1..x.len-3:
newFor.add x[i]
# transform enumerate(X) to 'X'
newFor.add x[^2][1]
newFor.add body
result.add newFor
for a, b in enumerate(items([1, 2, 3])):
echo a, " ", b
for a2, b2 in enumerate([1, 2, 3, 5]):
echo a2, " ", b2
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