ast.go RawHistoryFolder

1// SPDX-License-Identifier: MIT
2
3package expr
4
5// Node is a node of a parsed expression. The concrete types are [*Literal],
6// [*Unary], [*FunctionCall], [*Binary], [*Logical], [*Grouping],
7// [*ContextAccess], [*IndexAccess] and [*Star].
8type Node interface {
9	isNode()
10}
11
12// Literal is a null, boolean, number or string constant.
13type Literal struct {
14	Value Value
15	Token Token
16}
17
18// Unary is a negation: "!x".
19type Unary struct {
20	Operator Token
21	Expr     Node
22}
23
24// FunctionCall is a call such as "contains(a, b)". Name is the identifier
25// token as written; function names are case-insensitive.
26type FunctionCall struct {
27	Name Token
28	Args []Node
29}
30
31// Binary is a comparison: ==, !=, <, <=, > or >=.
32type Binary struct {
33	Left     Node
34	Operator Token
35	Right    Node
36}
37
38// Logical is a chain of && or || operands. The chain is flat: "a || b || c"
39// is one Logical with three Args. Operator is the first operator token.
40type Logical struct {
41	Operator Token
42	Args     []Node
43}
44
45// Grouping is a parenthesized expression.
46type Grouping struct {
47	Group Node
48}
49
50// ContextAccess is the name of a context, such as "github".
51type ContextAccess struct {
52	Name Token
53}
54
55// IndexAccess is "expr[index]" or "expr.name" (Index is then a string
56// [Literal]) or "expr.*" (Index is a [Star]).
57type IndexAccess struct {
58	Expr  Node
59	Index Node
60}
61
62// Star is the "*" of "expr.*" and "expr[*]".
63type Star struct{}
64
65func (*Literal) isNode()       {}
66func (*Unary) isNode()         {}
67func (*FunctionCall) isNode()  {}
68func (*Binary) isNode()        {}
69func (*Logical) isNode()       {}
70func (*Grouping) isNode()      {}
71func (*ContextAccess) isNode() {}
72func (*IndexAccess) isNode()   {}
73func (*Star) isNode()          {}