func libSubstr(th *eval.Thread, in []eval.Value, out []eval.Value) {
s := in[0].String()
start, err := strconv.ParseInt(in[1].String(), 10, 32)
var res string
if err != nil {
panic(err)
}
end, err := strconv.ParseInt(in[2].String(), 10, 32)
if err != nil {
panic(err)
}
if int(start) < 0 {
newStart := len(s) + int(start)
res := s[newStart:len(s)]
out[0] = eval.ToValue(res)
return
}
if len(s) < int(end) {
res = s[start:]
out[0] = eval.ToValue(res)
return
}
res = s[start:end]
out[0] = eval.ToValue(res)
}
func libParseFloat(th *eval.Thread, in []eval.Value, out []eval.Value) {
res, err := strconv.ParseFloat(in[0].String(), 64)
if err != nil {
panic(err)
}
out[0] = eval.ToValue(float64(res))
}
func libRandInt(th *eval.Thread, in []eval.Value, out []eval.Value) {
res, err := strconv.ParseInt(in[0].String(), 10, 64)
if err != nil {
panic(err)
}
v := int(rand.Float64() * float64(res))
out[0] = eval.ToValue(v)
}
func AbtabGrepMakeExpressionFilter(inp *AbtabURL, expr string) AbtabFilterFn {
var fset = token.NewFileSet()
w := eval.NewWorld()
InstallStandardLibrary(w)
var vars map[string]*eval.Variable = make(map[string]*eval.Variable, 1)
var empty = ""
var lnum int
v, _ := w.DefineVar("__LINE__", eval.TypeOfNative(lnum), eval.ToValue(lnum))
vars["__LINE__"] = v
for _, fname := range inp.Header {
v, _ := w.DefineVar(ScrubFieldNameForEval(fname), eval.TypeOfNative(empty), eval.ToValue(empty))
vars[fname] = v
}
return func(rec *Rec) (bool, error) {
// NB: this seems expensive, can we just re-assign to the internal var ref?
for idx, fname := range inp.Header {
var value = rec.Fields[idx]
vars[fname].Init = eval.ToValue(value)
}
//fmt.Fprintf(os.Stderr, "setting __LINE__=%d\n", rec.LineNum)
vars["__LINE__"].Init = eval.ToValue(int(rec.LineNum))
// NB: this seems expensive, can we compile once?
code, err := w.Compile(fset, expr)
if err != nil {
return false, err
}
v, err := code.Run()
if err != nil {
return false, err
}
if v.String() == "true" {
return true, nil
}
return false, nil
}
}
func libRandFloat(th *eval.Thread, in []eval.Value, out []eval.Value) {
out[0] = eval.ToValue(rand.Float64())
}