// compiles a binary expression x 'op' y
func (w *World) compileBinaryExpr(n *ast.BinaryExpr) Expr {
switch n.Op {
default:
panic(err(n.Pos(), "not allowed:", n.Op))
case token.ADD:
return &add{w.newBinExpr(n)}
case token.SUB:
return &sub{w.newBinExpr(n)}
case token.MUL:
return &mul{w.newBinExpr(n)}
case token.QUO:
return &quo{w.newBinExpr(n)}
case token.LSS:
return &lss{w.newComp(n)}
case token.GTR:
return >r{w.newComp(n)}
case token.LEQ:
return &leq{w.newComp(n)}
case token.GEQ:
return &geq{w.newComp(n)}
case token.EQL:
return &eql{w.newComp(n)}
case token.NEQ:
return &neq{w.newComp(n)}
case token.LAND:
return &and{w.newBoolOp(n)}
case token.LOR:
return &or{w.newBoolOp(n)}
}
}
func (f *File) checkNilFuncComparison(e *ast.BinaryExpr) {
if !vet("nilfunc") {
return
}
// Only want == or != comparisons.
if e.Op != token.EQL && e.Op != token.NEQ {
return
}
// Only want comparisons with a nil identifier on one side.
var e2 ast.Expr
switch {
case f.isNil(e.X):
e2 = e.Y
case f.isNil(e.Y):
e2 = e.X
default:
return
}
// Only want identifiers or selector expressions.
var obj types.Object
switch v := e2.(type) {
case *ast.Ident:
obj = f.pkg.idents[v]
case *ast.SelectorExpr:
obj = f.pkg.idents[v.Sel]
default:
return
}
// Only want functions.
if _, ok := obj.(*types.Func); !ok {
return
}
f.Badf(e.Pos(), "comparison of function %v %v nil is always %v", obj.Name(), e.Op, e.Op == token.NEQ)
}
func (w *World) newBoolOp(n *ast.BinaryExpr) boolOp {
x := typeConv(n.Pos(), w.compileExpr(n.X), bool_t)
y := typeConv(n.Pos(), w.compileExpr(n.Y), bool_t)
return boolOp{x, y}
}
func (w *World) newBinExpr(n *ast.BinaryExpr) binaryExpr {
x := typeConv(n.Pos(), w.compileExpr(n.X), float64_t)
y := typeConv(n.Pos(), w.compileExpr(n.Y), float64_t)
return binaryExpr{x, y}
}