44 lines
959 B
Go
44 lines
959 B
Go
package ast
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import (
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"fmt"
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)
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// Node is the interface that all AST nodes must implement.
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type Node interface {
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// Accept is called to dispatch to the visitors.
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Accept(Visitor)
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// Pos returns the position of this node in some source.
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Pos() Pos
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}
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// Pos is the starting position of an AST node
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type Pos struct {
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Column, Line int // Column/Line number, starting at 1
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}
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func (p Pos) String() string {
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return fmt.Sprintf("%d:%d", p.Line, p.Column)
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}
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// Visitors are just implementations of this function.
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//
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// Note that this isn't a true implementation of the visitor pattern, which
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// generally requires proper type dispatch on the function. However,
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// implementing this basic visitor pattern style is still very useful even
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// if you have to type switch.
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type Visitor func(Node)
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//go:generate stringer -type=Type
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// Type is the type of a literal.
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type Type uint
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const (
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TypeInvalid Type = 0
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TypeString Type = 1 << iota
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TypeInt
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TypeFloat
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)
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