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#
#
# The Nimrod Compiler
# (c) Copyright 2014 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements common simple lowerings.
const
genPrefix* = ":tmp" # prefix for generated names
import ast, types, idents, magicsys
proc newTupleAccess*(tup: PNode, i: int): PNode =
result = newNodeIT(nkBracketExpr, tup.info, tup.typ.skipTypes(
abstractInst).sons[i])
addSon(result, copyTree(tup))
var lit = newNodeIT(nkIntLit, tup.info, getSysType(tyInt))
lit.intVal = i
addSon(result, lit)
proc addVar*(father, v: PNode) =
var vpart = newNodeI(nkIdentDefs, v.info, 3)
vpart.sons[0] = v
vpart.sons[1] = ast.emptyNode
vpart.sons[2] = ast.emptyNode
addSon(father, vpart)
proc newAsgnStmt(le, ri: PNode): PNode =
result = newNodeI(nkAsgn, le.info, 2)
result.sons[0] = le
result.sons[1] = ri
proc lowerTupleUnpacking*(n: PNode; owner: PSym): PNode =
assert n.kind == nkVarTuple
let value = n.lastSon
result = newNodeI(nkStmtList, n.info)
var temp = newSym(skTemp, getIdent(genPrefix), owner, value.info)
temp.typ = skipTypes(value.typ, abstractInst)
incl(temp.flags, sfFromGeneric)
var v = newNodeI(nkVarSection, value.info)
v.addVar(newSymNode(temp))
result.add(v)
result.add newAsgnStmt(newSymNode(temp), value)
for i in 0 .. n.len-3:
result.add newAsgnStmt(n.sons[i], newTupleAccess(value, i))
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