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Commit | Line | Data |
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bae9f6d2 JC |
1 | package ast |
2 | ||
3 | import ( | |
4 | "fmt" | |
5 | "strings" | |
6 | ) | |
7 | ||
8 | // Index represents an indexing operation into another data structure | |
9 | type Index struct { | |
10 | Target Node | |
11 | Key Node | |
12 | Posx Pos | |
13 | } | |
14 | ||
15 | func (n *Index) Accept(v Visitor) Node { | |
16 | n.Target = n.Target.Accept(v) | |
17 | n.Key = n.Key.Accept(v) | |
18 | return v(n) | |
19 | } | |
20 | ||
21 | func (n *Index) Pos() Pos { | |
22 | return n.Posx | |
23 | } | |
24 | ||
25 | func (n *Index) String() string { | |
26 | return fmt.Sprintf("Index(%s, %s)", n.Target, n.Key) | |
27 | } | |
28 | ||
29 | func (n *Index) Type(s Scope) (Type, error) { | |
30 | variableAccess, ok := n.Target.(*VariableAccess) | |
31 | if !ok { | |
32 | return TypeInvalid, fmt.Errorf("target is not a variable") | |
33 | } | |
34 | ||
35 | variable, ok := s.LookupVar(variableAccess.Name) | |
36 | if !ok { | |
37 | return TypeInvalid, fmt.Errorf("unknown variable accessed: %s", variableAccess.Name) | |
38 | } | |
39 | ||
40 | switch variable.Type { | |
41 | case TypeList: | |
42 | return n.typeList(variable, variableAccess.Name) | |
43 | case TypeMap: | |
44 | return n.typeMap(variable, variableAccess.Name) | |
45 | default: | |
46 | return TypeInvalid, fmt.Errorf("invalid index operation into non-indexable type: %s", variable.Type) | |
47 | } | |
48 | } | |
49 | ||
50 | func (n *Index) typeList(variable Variable, variableName string) (Type, error) { | |
51 | // We assume type checking has already determined that this is a list | |
52 | list := variable.Value.([]Variable) | |
53 | ||
54 | return VariableListElementTypesAreHomogenous(variableName, list) | |
55 | } | |
56 | ||
57 | func (n *Index) typeMap(variable Variable, variableName string) (Type, error) { | |
58 | // We assume type checking has already determined that this is a map | |
59 | vmap := variable.Value.(map[string]Variable) | |
60 | ||
61 | return VariableMapValueTypesAreHomogenous(variableName, vmap) | |
62 | } | |
63 | ||
64 | func reportTypes(typesFound map[Type]struct{}) string { | |
65 | stringTypes := make([]string, len(typesFound)) | |
66 | i := 0 | |
67 | for k, _ := range typesFound { | |
68 | stringTypes[0] = k.String() | |
69 | i++ | |
70 | } | |
71 | return strings.Join(stringTypes, ", ") | |
72 | } | |
73 | ||
74 | func (n *Index) GoString() string { | |
75 | return fmt.Sprintf("*%#v", *n) | |
76 | } |