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prototype: no channels #54

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12 changes: 6 additions & 6 deletions Makefile
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Original file line number Diff line number Diff line change
@@ -1,15 +1,15 @@
export GOPATH := $(abspath ../..)
export NEX := $(abspath ../../bin/nex)
export GOPATH := $(abspath ../../../..)
export NEX := $(abspath ../../../../bin/nex)

all: $(NEX) test

$(NEX): main.go nex.go
go fmt nex
go install nex
go fmt github.com/blynn/nex
go install github.com/blynn/nex

test: $(NEX) $(shell find test -type f)
go fmt nex nex/test
go test nex nex/test
go fmt github.com/blynn/nex github.com/blynn/nex/test
go test github.com/blynn/nex github.com/blynn/nex/test

@dragonsinth dragonsinth Oct 16, 2019

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Uunrelated, but this makefile doesn't work when you pull the repo via a normal go get github.com/blynn/nex. This only works when you promote nex directly to go/src/nex which is unusual. We can revert this if needed.


clean:
rm -f $(NEX)
Expand Down
73 changes: 22 additions & 51 deletions nex.go
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Original file line number Diff line number Diff line change
Expand Up @@ -442,9 +442,9 @@ func gen(out *bufio.Writer, x *rule) {
newNilEdge(end, nend)
end = nend
case '?':
nstart := newNode()
nstart := newNode()
newNilEdge(nstart, start)
start = nstart
start = nstart
newNilEdge(start, end)
default:
return
Expand Down Expand Up @@ -523,7 +523,7 @@ func gen(out *bufio.Writer, x *rule) {
visited := make([]bool, n)
var do func(int)
do = func(i int) {
visited[i] = true
visited[i] = true
v := short[i]
for _, e := range v.e {
if e.kind == kNil && !visited[e.dst.n] {
Expand Down Expand Up @@ -735,10 +735,13 @@ func writeFamily(out *bufio.Writer, node *rule, lvl int) {
out.WriteString("}\n")
}
tab()
fmt.Fprintf(out, "OUTER%s%d:\n", node.id, lvl)
out.WriteString("defer func() { _ = recover() }()\n")
tab()
prefixReplacer.WriteString(out,
fmt.Sprintf("for { switch yylex.next(%v) {\n", lvl))
prefixReplacer.WriteString(out, "yylex.scan(func(fr frame) {\n")
tab()
prefixReplacer.WriteString(out, "defer yylex.pop()\n")
tab()
prefixReplacer.WriteString(out, fmt.Sprintf("switch yylex.next(%v, fr) {\n", lvl))
for i, x := range node.kid {
tab()
fmt.Fprintf(out, "\tcase %d:\n", i)
Expand All @@ -754,17 +757,11 @@ func writeFamily(out *bufio.Writer, node *rule, lvl int) {
tab()
out.WriteString("\tdefault:\n")
tab()
fmt.Fprintf(out, "\t\t break OUTER%s%d\n", node.id, lvl)
fmt.Fprintf(out, "\t\t panic(\"exit %s%d\")\n", node.id, lvl)
tab()
out.WriteString("\t}\n")
tab()
out.WriteString("\tcontinue\n")
tab()
out.WriteString("}\n")
tab()
prefixReplacer.WriteString(out, "yylex.pop()\n")
tab()
out.WriteString(node.endCode + "\n")
out.WriteString("})\n")
}

var lexertext = `import ("bufio";"io";"strings")
Expand All @@ -774,13 +771,11 @@ type frame struct {
line, column int
}
type Lexer struct {
// The lexer runs in its own goroutine, and communicates via channel 'ch'.
ch chan frame
ch_stop chan bool
// The lexer emits tokens through a supplied callback.
scan func(func(frame))
// We record the level of nesting because the action could return, and a
// subsequent call expects to pick up where it left off. In other words,
// we're simulating a coroutine.
// TODO: Support a channel-based variant that compatible with Go's yacc.
stack []frame
stale bool

Expand All @@ -803,10 +798,8 @@ func NewLexerWithInit(in io.Reader, initFun func(*Lexer)) *Lexer {
if initFun != nil {
initFun(yylex)
}
yylex.ch = make(chan frame)
yylex.ch_stop = make(chan bool, 1)
var scan func(in *bufio.Reader, ch chan frame, ch_stop chan bool, family []dfa, line, column int)
scan = func(in *bufio.Reader, ch chan frame, ch_stop chan bool, family []dfa, line, column int) {
var scan func(in *bufio.Reader, f func(frame), family []dfa, line, column int)
scan = func(in *bufio.Reader, f func(frame), family []dfa, line, column int) {
// Index of DFA and length of highest-precedence match so far.
matchi, matchn := 0, -1
var buf []rune
Expand Down Expand Up @@ -835,7 +828,6 @@ func NewLexerWithInit(in io.Reader, initFun func(*Lexer)) *Lexer {
}
}
atEOF := false
stopped := false
for {
if n == len(buf) && !atEOF {
r,_,err := in.ReadRune()
Expand Down Expand Up @@ -893,27 +885,9 @@ dollar: // Handle $.
text := string(buf[:matchn])
buf = buf[matchn:]
matchn = -1
for {
sent := false
select {
case ch <- frame{matchi, text, line, column}: {
sent = true
}
case stopped = <- ch_stop: {
}
default: {
// nothing
}
}
if stopped||sent {
break
}
}
if stopped {
break
}
f(frame{matchi, text, line, column})
if len(family[matchi].nest) > 0 {
scan(bufio.NewReader(strings.NewReader(text)), ch, ch_stop, family[matchi].nest, line, column)
scan(bufio.NewReader(strings.NewReader(text)), f, family[matchi].nest, line, column)
}
if atEOF {
break
Expand All @@ -928,9 +902,10 @@ dollar: // Handle $.
}
}
}
ch <- frame{-1, "", line, column}
}
go scan(bufio.NewReader(in), yylex.ch, yylex.ch_stop, dfas, 0, 0)
yylex.scan = func(f func(frame)) {
scan(bufio.NewReader(in), f, dfas, 0, 0)
}
return yylex
}

Expand All @@ -949,10 +924,6 @@ func NewLexer(in io.Reader) *Lexer {
return NewLexerWithInit(in, nil)
}

func (yyLex *Lexer) Stop() {
yyLex.ch_stop <- true
}

// Text returns the matched text.
func (yylex *Lexer) Text() string {
return yylex.stack[len(yylex.stack) - 1].s
Expand All @@ -976,7 +947,7 @@ func (yylex *Lexer) Column() int {
return yylex.stack[len(yylex.stack) - 1].column
}

func (yylex *Lexer) next(lvl int) int {
func (yylex *Lexer) next(lvl int, fr frame) int {
if lvl == len(yylex.stack) {
l, c := 0, 0
if lvl > 0 {
Expand All @@ -986,7 +957,7 @@ func (yylex *Lexer) next(lvl int) int {
}
if lvl == len(yylex.stack) - 1 {
p := &yylex.stack[lvl]
*p = <-yylex.ch
*p = fr
yylex.stale = false
} else {
yylex.stale = true
Expand Down