62 lines
1.1 KiB
Nim
62 lines
1.1 KiB
Nim
import macros
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proc newIfElse(c, t, e: NimNode): NimNode {.compiletime.} =
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result = newIfStmt((c, t))
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result.add(newNimNode(nnkElse).add(e))
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macro if2(x, y: bool; z: untyped): untyped =
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var parts: array[4, NimNode]
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for i in parts.low .. parts.high:
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parts[i] = newNimNode(nnkDiscardStmt).add(NimNode(nil))
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assert z.kind == nnkStmtList
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assert z.len <= 4
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for i in 0 ..< z.len:
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assert z[i].kind == nnkCall
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assert z[i].len == 2
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var j = 0
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case $z[i][0]
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of "then": j = 0
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of "else1": j = 1
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of "else2": j = 2
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of "else3": j = 3
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else: assert false
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parts[j] = z[i][1].last
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result = newIfElse(x,
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newIfElse(y, parts[0], parts[1]),
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newIfElse(y, parts[2], parts[3]))
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if2 2 > 1, 3 < 2:
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then:
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echo "1"
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else1:
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echo "2"
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else2:
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echo "3"
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else3:
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echo "4"
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# Missing cases are supported:
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if2 2 > 1, 3 < 2:
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then:
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echo "1"
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else2:
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echo "3"
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else3:
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echo "4"
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# Order can be swapped:
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if2 2 > 1, 3 < 2:
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then:
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echo "1"
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else2:
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echo "3"
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else1:
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echo "2"
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else3:
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echo "4"
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