82 lines
1.5 KiB
Go
82 lines
1.5 KiB
Go
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package varaq
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import (
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"fmt"
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"strings"
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)
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type Expr struct {
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Tok TokenType
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Exprs []Expr
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Value any
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Count int
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}
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type Parser struct {
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tokens []Token
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pos int
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end int
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}
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func (p Parser) curr() Token {
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return p.tokens[p.pos]
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}
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func parse(p Parser, stop TokenType, tt TokenType) (Expr, int) {
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code := Expr{tt, make([]Expr, 0), nil, 0}
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for {
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if p.pos < 0 || p.pos > p.end-1 {
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break
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}
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if p.curr().Toktype == stop {
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p.pos += 1
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break
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}
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if p.curr().Toktype == LEFTBRACE {
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p.pos += 1
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ex, pos := parse(p, RIGHTBRACE, FUNCTION)
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p.pos = pos
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code.Exprs = append(code.Exprs, ex)
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code.Count += 1
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} else if p.curr().Toktype == LEFTPAREN {
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p.pos += 1
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ex, pos := parse(p, RIGHTPAREN, LIST)
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p.pos = pos
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code.Exprs = append(code.Exprs, ex)
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code.Count += 1
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} else {
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code.Exprs = append(code.Exprs, Expr{p.curr().Toktype, nil, p.curr().Literal, 0})
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p.pos += 1
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}
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}
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return code, p.pos
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}
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func Parse(tokens []Token) Expr {
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parser := Parser{tokens, 0, len(tokens)}
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ex, _ := parse(parser, EOF, SCRIPT)
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return ex
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}
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func PrintDump(code Expr, depth int) {
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for _, c := range code.Exprs {
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if c.Tok == FUNCTION {
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depth += 1
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fmt.Printf("%s %s\n", strings.Repeat("-", depth), c.Tok)
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PrintDump(c, depth)
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depth -= 1
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} else if c.Tok == LIST {
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depth += 1
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fmt.Printf("%s %s\n", strings.Repeat("-", depth), c.Tok)
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PrintDump(c, depth)
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depth -= 1
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} else {
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fmt.Printf("%s %s: %v\n", strings.Repeat("-", depth), c.Tok, c.Value)
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}
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}
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}
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