-
Notifications
You must be signed in to change notification settings - Fork 0
/
locator.go
105 lines (91 loc) · 2.03 KB
/
locator.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
package gts
import (
"errors"
"strings"
"github.com/go-pars/pars"
)
// Locator is a function that maps features to its regions.
type Locator func(seq Sequence) Regions
func allLocator(seq Sequence) Regions {
ff := seq.Features()
rr := make(Regions, len(ff))
for i, f := range ff {
rr[i] = f.Loc.Region()
}
return rr
}
func resizeLocator(locate Locator, mod Modifier) Locator {
return func(seq Sequence) Regions {
rr := locate(seq)
for i, r := range rr {
rr[i] = r.Resize(mod)
}
return rr
}
}
func relativeLocator(mod Modifier) Locator {
return func(seq Sequence) Regions {
seg := Segment{0, Len(seq)}
return Regions{seg.Resize(mod)}
}
}
func locationLocator(loc Location) Locator {
return func(seq Sequence) Regions {
return Regions{loc.Region()}
}
}
func filterLocator(f Filter) Locator {
return func(seq Sequence) Regions {
ff := seq.Features()
ff = ff.Filter(f)
rr := make(Regions, len(ff))
for i, f := range ff {
rr[i] = f.Loc.Region()
}
return rr
}
}
func tryLocation(s string) (Location, bool) {
var parser pars.Parser
parser = pars.Any(parseComplement(&parser), parseRange, parsePoint)
result, err := parser.Parse(pars.FromString(s))
if err != nil {
return nil, false
}
return result.Value.(Location), true
}
// AsLocator interprets the given string as a Locator.
func AsLocator(s string) (Locator, error) {
switch i := strings.IndexByte(s, '@'); i {
case -1:
mod, err := AsModifier(s)
if err == nil {
return relativeLocator(mod), nil
}
loc, ok := tryLocation(s)
if ok {
return locationLocator(loc), nil
}
sel, err := Selector(s)
if err == nil {
return filterLocator(sel), nil
}
return nil, errors.New("expected a selector or locator")
case 0:
mod, err := AsModifier(s[1:])
if err != nil {
return nil, err
}
return resizeLocator(allLocator, mod), nil
default:
locate, err := AsLocator(s[:i])
if err != nil {
return nil, err
}
mod, err := AsModifier(s[i+1:])
if err != nil {
return nil, err
}
return resizeLocator(locate, mod), nil
}
}