Function compileBranchCondition

compile.go:932–978

}}}

(context *funcContext, reg int, expr ast.Expr, thenlabel, elselabel int, hasnextcond bool)

} // }}}

func compileBranchCondition(context *funcContext, reg int, expr ast.Expr, thenlabel, elselabel int, hasnextcond bool) { // {{{
	// TODO folding constants?
	code := context.Code
	flip := 0
	jumplabel := elselabel
	if hasnextcond {
		flip = 1
		jumplabel = thenlabel
	}

	switch ex := expr.(type) {
	case *ast.FalseExpr, *ast.NilExpr:
		if !hasnextcond {
			code.AddASbx(OP_JMP, 0, elselabel, sline(expr))
			return
		}
	case *ast.TrueExpr, *ast.NumberExpr, *ast.StringExpr:
		if !hasnextcond {
			return
		}
	case *ast.UnaryNotOpExpr:
		compileBranchCondition(context, reg, ex.Expr, elselabel, thenlabel, !hasnextcond)
		return
	case *ast.LogicalOpExpr:
		switch ex.Operator {
		case "and":
			nextcondlabel := context.NewLabel()
			compileBranchCondition(context, reg, ex.Lhs, nextcondlabel, elselabel, false)
			context.SetLabelPc(nextcondlabel, context.Code.LastPC())
			compileBranchCondition(context, reg, ex.Rhs, thenlabel, elselabel, hasnextcond)
		case "or":
			nextcondlabel := context.NewLabel()
			compileBranchCondition(context, reg, ex.Lhs, thenlabel, nextcondlabel, true)
			context.SetLabelPc(nextcondlabel, context.Code.LastPC())
			compileBranchCondition(context, reg, ex.Rhs, thenlabel, elselabel, hasnextcond)
		}
		return
	case *ast.RelationalOpExpr:
		compileRelationalOpExprAux(context, reg, ex, flip, jumplabel)
		return
	}

	a := reg
	compileExprWithMVPropagation(context, expr, &reg, &a)
	code.AddABC(OP_TEST, a, 0, 0^flip, sline(expr))
	code.AddASbx(OP_JMP, 0, jumplabel, sline(expr))
} // }}}

func compileWhileStmt(context *funcContext, stmt *ast.WhileStmt) { // {{{
	thenlabel := context.NewLabel()