-
Notifications
You must be signed in to change notification settings - Fork 45
/
codegen.go
195 lines (172 loc) · 4 KB
/
codegen.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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
package ebnfparser
import (
"fmt"
"strings"
"github.com/hashicorp/hcl/hcl/strconv"
"github.com/spf13/afero"
"github.com/anz-bank/sysl/pkg/eval"
"github.com/anz-bank/sysl/pkg/sysl"
"github.com/sirupsen/logrus"
)
type EbnfGrammar struct {
Rules map[string][]TermNode
Start string
}
func ReadGrammar(fs afero.Fs, filename string, start string) (*EbnfGrammar, error) {
grammar, err := afero.ReadFile(fs, filename)
if err != nil {
return nil, err
}
g, err := ParseString(string(grammar))
if err != nil {
return nil, err
}
res := EbnfGrammar{
Rules: map[string][]TermNode{},
Start: start,
}
WalkerOps{EnterProdNode: func(node ProdNode) Stopper {
res.Rules[node.OneIdent().String()] = node.AllTerm()
return nil
}}.Walk(g)
_, has := res.Rules[start]
if !has {
return nil, fmt.Errorf("start rule '%s' not defined", start)
}
return &res, nil
}
func GenerateOutput(grammar *EbnfGrammar, value *sysl.Value, logger *logrus.Logger) (string, error) {
return walk(grammar.Rules[grammar.Start], value, grammar.Rules, logger)
}
type walker struct {
WalkerOps
logger *logrus.Logger
rules map[string][]TermNode
out []string
err error
value *sysl.Value
}
func walk(terms []TermNode, val *sysl.Value, rules map[string][]TermNode, logger *logrus.Logger) (string, error) {
w := walker{
logger: logger,
value: val,
rules: rules,
}
w.WalkerOps = WalkerOps{
EnterTermNode: w.EnterTermNode,
EnterStringNode: func(node StringNode) Stopper {
s, err := strconv.Unquote(node.String())
if err != nil {
s = node.String()
}
s = strings.NewReplacer("\\n", "\n", "\\t", "\t").Replace(s)
w.addToken(s)
return nil
},
}
for _, t := range terms {
w.WalkerOps.WalkTermNode(t)
}
return strings.TrimRight(strings.Join(w.out, " "), " "), w.err
}
func (w walker) findRule(name string) []TermNode {
out, has := w.rules[name]
if has {
return out
}
return nil
}
func (w *walker) addToken(s string) {
w.out = append(w.out, s)
}
func (w *walker) EnterTermNode(node TermNode) Stopper {
if node.OneOp() != "" {
// handle choices
for _, option := range node.AllTerm() {
out, err := walk([]TermNode{option}, w.value, w.rules, w.logger)
if err == nil {
w.addToken(out)
return &nodeExiter{}
}
}
w.err = fmt.Errorf("none of the options were satisfied")
return Aborter
}
min := 1
max := 1
if node.OneQuant() != nil {
switch node.OneQuant().OneToken() {
case "*":
min = 0
max = 0
case "?":
min = 0
case "+":
max = 0
}
}
if atom := node.OneAtom(); atom != nil {
if id := atom.OneRule().String(); id != "" {
obj := getValue(id, w.value)
if obj == nil {
if min == 1 {
w.err = fmt.Errorf("expected a '%s' but none found", id)
return Aborter
}
return nil
}
if !eval.IsCollectionType(obj) {
obj = eval.MakeValueList(obj)
}
vals := eval.GetValueSlice(obj)
if max == 1 && len(vals) > 1 {
w.err = fmt.Errorf("expected a single '%s' but %d found", id, len(vals))
return Aborter
} else if min == 1 && len(vals) == 0 {
w.err = fmt.Errorf("expected a '%s' but none found", id)
return Aborter
}
var fn func(string, *sysl.Value) error
if next := w.findRule(id); next != nil {
fn = w.applyRule
} else {
fn = func(s string, value *sysl.Value) error {
w.addToken(getValue(s, value).GetS())
return nil
}
}
for _, v := range vals {
err := fn(id, v)
w.err = err
if err != nil {
return Aborter
}
}
}
}
return nil
}
func (w *walker) applyRule(name string, value *sysl.Value) error {
next := w.findRule(name)
s, err := walk(next, value, w.rules, w.logger)
if err != nil {
return err
}
w.addToken(s)
return nil
}
func getValue(name string, value *sysl.Value) *sysl.Value {
switch v := value.Value.(type) {
case *sysl.Value_Map_:
if v, has := v.Map.Items[name]; has {
return v
}
case *sysl.Value_S:
return value
default:
// Should we convert int and bools to string and return?
// return eval.UnaryString(value)
return nil
}
return nil
}