// parseConstants finds constant definitions and references to them.
// It replaces the references with the nodes denoting the value of
// the respective constants.
func parseConstants(ast *parser.AST, list []parser.Node) (out []parser.Node, err error) {
var instr *parser.Instruction
var expr *parser.Expression
var name *parser.Name
var ok bool
consts := make(map[string][]parser.Node)
for i := 0; i < len(list); i++ {
if instr, ok = list[i].(*parser.Instruction); !ok {
continue
}
name = instr.Children()[0].(*parser.Name)
if name.Data != "equ" {
continue
}
expr = instr.Children()[1].(*parser.Expression)
name = expr.Children()[0].(*parser.Name)
if _, ok = consts[name.Data]; ok {
return nil, NewBuildError(
ast.Files[instr.File()], instr.Line(), instr.Col(),
"Duplicate constant %q.", name.Data)
}
expr = instr.Children()[2].(*parser.Expression)
consts[name.Data] = expr.Children()
// Remove constant node from AST.
copy(list[i:], list[i+1:])
list = list[:len(list)-1]
i--
}
for k, v := range consts {
list = replaceConstantRef(list, k, v)
}
return list, nil
}
func (sw *SourceWriter) writeExpression(n *parser.Expression) {
sw.writeList(n.Children())
}