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160 lines
2.7 KiB
Go
160 lines
2.7 KiB
Go
package main
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import (
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"bytes"
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"fmt"
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)
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type nodeType int
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const (
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n_error nodeType = iota
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n_root
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n_comment
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n_assignment
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)
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type node interface {
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Type() nodeType
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parse(*parser) error
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}
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type rootNode struct {
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children []node
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}
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func newRootNode() node {
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return &rootNode{children: make([]node, 0, 8)}
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}
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func (n *rootNode) Type() nodeType {
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return n_root
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}
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func (n *rootNode) parse(p *parser) error {
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for {
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t := p.next()
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switch t.t {
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case t_error:
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return fmt.Errorf("parse error: saw lex error while parsing root node: %v", t.s)
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case t_eof:
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return nil
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case t_comment:
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shit := commentNode(t.s)
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n.addChild(&shit)
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case t_name:
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nn := &assignmentNode{name: t.s}
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if err := nn.parse(p); err != nil {
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return err
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}
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n.addChild(nn)
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default:
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return fmt.Errorf("parse error: unexpected token type %v while parsing root node", t.t)
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}
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}
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}
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func (n *rootNode) addChild(child node) {
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if n.children == nil {
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n.children = make([]node, 0, 8)
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}
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n.children = append(n.children, child)
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}
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func (n *rootNode) String() string {
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var buf bytes.Buffer
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buf.WriteString("{")
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for _, child := range n.children {
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fmt.Fprintf(&buf, "%s, ", child)
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}
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if buf.Len() > 1 {
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buf.Truncate(buf.Len() - 2)
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}
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buf.WriteString("}")
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return buf.String()
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}
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type commentNode string
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func (n commentNode) Type() nodeType {
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return n_comment
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}
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func (n commentNode) parse(p *parser) error {
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return nil
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}
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func (n commentNode) String() string {
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return fmt.Sprintf("{comment: %s}", string(n))
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}
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type assignmentNode struct {
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name string
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value interface{}
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}
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func (n assignmentNode) Type() nodeType {
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return n_assignment
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}
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func (n *assignmentNode) parse(p *parser) error {
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t := p.next()
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switch t.t {
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case t_error:
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return fmt.Errorf("parse error: saw lex error while parsing assignment node: %v", t.s)
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case t_eof:
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return fmt.Errorf("parse error: unexpected eof in assignment node")
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case t_equals:
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default:
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return fmt.Errorf("parse error: unexpected %v token after name, expected =", t.t)
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}
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v, err := p.parseValue()
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if err != nil {
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return err
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}
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n.value = v
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return nil
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}
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func (n *assignmentNode) String() string {
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return fmt.Sprintf("{assign: name=%s, val=%s}", n.name, n.value)
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}
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type list struct {
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head *listElem
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tail *listElem
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}
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func (l list) String() string {
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var buf bytes.Buffer
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buf.WriteString("[")
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for e := l.head; e != nil; e = e.next {
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fmt.Fprintf(&buf, "%v, ", e.value)
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}
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if buf.Len() > 1 {
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buf.Truncate(buf.Len() - 2)
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}
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buf.WriteString("]")
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return buf.String()
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}
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func (l *list) append(v interface{}) {
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e := listElem{value: v}
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if l.head == nil {
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l.head = &e
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}
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if l.tail != nil {
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l.tail.next = &e
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e.prev = l.tail
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}
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l.tail = &e
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}
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type listElem struct {
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value interface{}
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prev *listElem
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next *listElem
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}
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