nasin/internal/styles/tss/flatten.go

54 lines
1.2 KiB
Go

package tss
import "fmt"
import "errors"
// Flatten evaluates all variables recursively, thereby eliminating all
// instances of ValueVariable.
func (this *Sheet) Flatten () error {
if this.flat { return nil }
this.flat = true
for name, variable := range this.Variables {
variable, err := this.eval(variable)
if err != nil { return err }
this.Variables[name] = variable
}
for index, rule := range this.Rules {
for name, attr := range rule.Attrs {
for index, list := range attr {
list, err := this.eval(list)
if err != nil { return err }
attr[index] = list
}
rule.Attrs[name] = attr
}
this.Rules[index] = rule
}
return nil
}
func (this *Sheet) eval (source ValueList) (ValueList, error) {
destination := make(ValueList, 0, len(source))
for _, value := range source {
if name, ok := value.(ValueVariable); ok {
variable, ok := this.Variables[string(name)]
if !ok {
return nil, errors.New(fmt.Sprintf(
"variable $%s does not exist",
value))
}
variable, err := this.eval(variable)
if err != nil { return nil, err }
destination = append(destination, variable...)
continue
} else {
destination = append(destination, value)
}
}
return destination, nil
}