From c5035ebd93db2e209abea321ec4f8a0968ede1fb Mon Sep 17 00:00:00 2001
From: chai2010 <chaishushan@gmail.com>
Date: Sun, 19 Feb 2023 23:15:29 +0800
Subject: [PATCH] =?UTF-8?q?yacc:=20expr=20=E4=BE=8B=E5=AD=90=E5=AE=8C?=
 =?UTF-8?q?=E5=96=84,=20=E5=8C=85=E5=90=AB=E7=94=9F=E6=88=90=E7=9A=84?=
 =?UTF-8?q?=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .gitignore                |   2 +-
 _examples/expr/Makefile   |   4 -
 _examples/expr/expr.y     |   2 +-
 _examples/expr/y.wa       | 551 ++++++++++++++++++++++++++++++++++++++
 internal/app/yacc/yacc.go |   2 +-
 5 files changed, 554 insertions(+), 7 deletions(-)
 create mode 100644 _examples/expr/y.wa

diff --git a/.gitignore b/.gitignore
index 73675e1..62ad190 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,7 +16,7 @@ wat2wasm.exe
 *.out*
 *.wasm
 *.wasm.*
-y.*
+y.wa.*
 
 /docs/snake/*
 
diff --git a/_examples/expr/Makefile b/_examples/expr/Makefile
index 5404c7f..b9dfce6 100644
--- a/_examples/expr/Makefile
+++ b/_examples/expr/Makefile
@@ -4,9 +4,5 @@ default:
 	go run ../../main.go yacc -l -p=expr -c="copyright.txt" -o="y.wa" expr.y
 	go run ../../main.go y.wa
 
-dev:
-	go run ../../main.go yacc -l -p=expr -c="copyright.txt" -o="y.wa.go" expr.y
-	go run y.wa.go
-
 clean:
 	-rm y.* a.out*
diff --git a/_examples/expr/expr.y b/_examples/expr/expr.y
index 0cdb39c..fdcc094 100644
--- a/_examples/expr/expr.y
+++ b/_examples/expr/expr.y
@@ -1,7 +1,7 @@
 // 版权 @2023 凹语言 作者。保留所有权利。
 
 %{
-package main
+// 这是 凹语言 yacc 的例子, 用于对表达式进行解析, 为了简化词法部分暂时通过手工录入.
 %}
 
 %union {
diff --git a/_examples/expr/y.wa b/_examples/expr/y.wa
new file mode 100644
index 0000000..af7c16e
--- /dev/null
+++ b/_examples/expr/y.wa
@@ -0,0 +1,551 @@
+// 版权 @2019 凹语言 作者。保留所有权利。
+
+// Code generated by 'wa yacc yacc -l -p=expr -c=copyright.txt -o=y.wa expr.y'. DO NOT EDIT.
+
+// 这是 凹语言 yacc 的例子, 用于对表达式进行解析, 为了简化词法部分暂时通过手工录入.
+
+import "strconv" => __yystrconv__
+
+type exprSymType struct {
+	yys :int
+	num :int
+}
+
+const NUM = 57346
+
+var exprToknames = [...]string{
+	"$end",
+	"error",
+	"$unk",
+	"'+'",
+	"'-'",
+	"'*'",
+	"'/'",
+	"'('",
+	"')'",
+	"NUM",
+}
+
+var exprStatenames = [...]string{}
+
+const exprEofCode = 1
+const exprErrCode = 2
+const exprInitialStackSize = 16
+
+// Lex 结束标志
+const eof = 0
+
+type exprToken struct {
+	Kind  :int
+	Value :int
+}
+
+type exprLexer struct {
+	tokens :[]exprToken
+	pos    :int
+}
+
+func (p: *exprLexer) Lex(yylval: *exprSymType) => int {
+	if p.pos >= len(p.tokens) {
+		return eof
+	}
+	tok := p.tokens[p.pos]
+	p.pos++
+
+	yylval.num = tok.Value
+	return tok.Kind
+}
+
+func (x: *exprLexer) Error(s: string) {
+	println("ERROR:", s)
+}
+
+func main() {
+	print("1+2*(3+4)-10 = ")
+	exprParse(&exprLexer{
+		tokens: []exprToken{
+			{Kind: NUM, Value: 1},
+			{Kind: '+'},
+			{Kind: NUM, Value: 2},
+			{Kind: '*'},
+			{Kind: '('},
+			{Kind: NUM, Value: 3},
+			{Kind: '+'},
+			{Kind: NUM, Value: 4},
+			{Kind: ')'},
+			{Kind: '-'},
+			{Kind: NUM, Value: 10},
+		},
+	})
+}
+
+var exprExca = [...]int{
+	-1, 1,
+	1, -1,
+	-2, 0,
+}
+
+const exprPrivate = 57344
+
+const exprLast = 23
+
+var exprAct = [...]int{
+	7, 4, 5, 2, 21, 9, 6, 8, 12, 13,
+	9, 1, 8, 16, 3, 19, 20, 17, 18, 14,
+	15, 10, 11,
+}
+
+var exprPact = [...]int{
+	-3, -1000, -1000, 17, -3, -3, 13, -1000, -1000, -3,
+	2, 2, -1000, -1000, 2, 2, -5, 13, 13, -1000,
+	-1000, -1000,
+}
+
+var exprPgo = [...]int{
+	0, 3, 14, 6, 0, 11,
+}
+
+var exprR1 = [...]int{
+	0, 5, 1, 1, 1, 2, 2, 2, 3, 3,
+	3, 4, 4,
+}
+
+var exprR2 = [...]int{
+	0, 1, 1, 2, 2, 1, 3, 3, 1, 3,
+	3, 1, 3,
+}
+
+var exprChk = [...]int{
+	-1000, -5, -1, -2, 4, 5, -3, -4, 10, 8,
+	4, 5, -1, -1, 6, 7, -1, -3, -3, -4,
+	-4, 9,
+}
+
+var exprDef = [...]int{
+	0, -2, 1, 2, 0, 0, 5, 8, 11, 0,
+	0, 0, 3, 4, 0, 0, 0, 6, 7, 9,
+	10, 12,
+}
+
+var exprTok1 = [...]int{
+	1, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	8, 9, 6, 4, 3, 5, 3, 7,
+}
+
+var exprTok2 = [...]int{
+	2, 3, 10,
+}
+
+var exprTok3 = [...]int{
+	0,
+}
+
+type exprErrorMessageInfo struct {
+	state :int
+	token :int
+	msg   :string
+}
+
+var exprErrorMessages = [...]exprErrorMessageInfo{}
+
+/*	parser for yacc output	*/
+
+var (
+	exprDebug        = 0
+	exprErrorVerbose = false
+)
+
+type exprParser struct {
+	lval  :exprSymType
+	stack :[exprInitialStackSize]exprSymType
+	char  :int
+}
+
+func (p: *exprParser) Lookahead() => int {
+	return p.char
+}
+
+func exprNewParser() => *exprParser {
+	return &exprParser{}
+}
+
+const exprFlag = -1000
+
+func exprTokname(c: int) => string {
+	if c >= 1 && c-1 < len(exprToknames) {
+		if exprToknames[c-1] != "" {
+			return exprToknames[c-1]
+		}
+	}
+	return "tok-" + __yystrconv__.Itoa(c)
+}
+
+func exprStatname(s: int) => string {
+	if s >= 0 && s < len(exprStatenames) {
+		if exprStatenames[s] != "" {
+			return exprStatenames[s]
+		}
+	}
+	return "state-" + __yystrconv__.Itoa(s)
+}
+
+func exprErrorMessage(state, lookAhead: int) => string {
+	const TOKSTART = 4
+
+	if !exprErrorVerbose {
+		return "syntax error"
+	}
+
+	for _, e := range exprErrorMessages {
+		if e.state == state && e.token == lookAhead {
+			return "syntax error: " + e.msg
+		}
+	}
+
+	res := "syntax error: unexpected " + exprTokname(lookAhead)
+
+	// To match Bison, suggest at most four expected tokens.
+	expected := make([]int, 0, 4)
+
+	// Look for shiftable tokens.
+	base := exprPact[state]
+	for tok := TOKSTART; tok-1 < len(exprToknames); tok++ {
+		if n := base + tok; n >= 0 && n < exprLast && exprChk[exprAct[n]] == tok {
+			if len(expected) == cap(expected) {
+				return res
+			}
+			expected = append(expected, tok)
+		}
+	}
+
+	if exprDef[state] == -2 {
+		i := 0
+		for exprExca[i] != -1 || exprExca[i+1] != state {
+			i += 2
+		}
+
+		// Look for tokens that we accept or reduce.
+		for i += 2; exprExca[i] >= 0; i += 2 {
+			tok := exprExca[i]
+			if tok < TOKSTART || exprExca[i+1] == 0 {
+				continue
+			}
+			if len(expected) == cap(expected) {
+				return res
+			}
+			expected = append(expected, tok)
+		}
+
+		// If the default action is to accept or reduce, give up.
+		if exprExca[i+1] != 0 {
+			return res
+		}
+	}
+
+	for i, tok := range expected {
+		if i == 0 {
+			res += ", expecting "
+		} else {
+			res += " or "
+		}
+		res += exprTokname(tok)
+	}
+	return res
+}
+
+func exprlex1(lex: *exprLexer, lval: *exprSymType) => (char, token: int) {
+	token = 0
+	char = lex.Lex(lval)
+
+out:
+	for {
+		if char <= 0 {
+			token = exprTok1[0]
+			break out
+		}
+		if char < len(exprTok1) {
+			token = exprTok1[char]
+			break out
+		}
+		if char >= exprPrivate {
+			if char < exprPrivate+len(exprTok2) {
+				token = exprTok2[char-exprPrivate]
+				break out
+			}
+		}
+		for i := 0; i < len(exprTok3); i += 2 {
+			token = exprTok3[i+0]
+			if token == char {
+				token = exprTok3[i+1]
+				break out
+			}
+		}
+		break out
+	}
+
+	if token == 0 {
+		token = exprTok2[1] /* unknown char */
+	}
+	if exprDebug >= 3 {
+		println("lex " + exprTokname(token) + "(" + __yystrconv__.Itoa(char) + ")")
+	}
+	return char, token
+}
+
+func exprParse(exprlex: *exprLexer) => int {
+	return exprNewParser().Parse(exprlex)
+}
+
+func (exprrcvr: *exprParser) Parse(exprlex: *exprLexer) => int {
+	var exprn: int
+	var exprVAL: exprSymType
+	var exprDollar: []exprSymType
+	_ = exprDollar // silence set and not used
+	exprS := exprrcvr.stack[:]
+
+	Nerrs := 0   /* number of errors */
+	Errflag := 0 /* error recovery flag */
+	exprstate := 0
+	exprrcvr.char = -1
+	exprtoken := -1 // exprrcvr.char translated into internal numbering
+	exprp := -1
+
+	const __goto_exprstack = -1
+	const __goto_exprnewstate = -2
+	const __goto_exprdefault = -3
+	var __goto_x = __goto_exprstack
+
+Loop:
+	for {
+		switch __goto_x {
+		case __goto_exprstack:
+			/* put a state and value onto the stack */
+			if exprDebug >= 4 {
+				println("char " + exprTokname(exprtoken) + " in " + exprStatname(exprstate))
+			}
+
+			exprp++
+			if exprp >= len(exprS) {
+				nyys := make([]exprSymType, len(exprS)*2)
+				for i := 0; i < len(exprS); i++ {
+					nyys[i] = exprS[i]
+				}
+				exprS = nyys
+			}
+			exprS[exprp] = exprVAL
+			exprS[exprp].yys = exprstate
+
+			__goto_x = __goto_exprnewstate
+			continue Loop
+
+		case __goto_exprnewstate:
+			exprn = exprPact[exprstate]
+			if exprn <= exprFlag {
+				/* simple state */
+				__goto_x = __goto_exprdefault
+				continue Loop
+			}
+			if exprrcvr.char < 0 {
+				exprrcvr.char, exprtoken = exprlex1(exprlex, &exprrcvr.lval)
+			}
+			exprn += exprtoken
+			if exprn < 0 || exprn >= exprLast {
+				__goto_x = __goto_exprdefault
+				continue Loop
+			}
+			exprn = exprAct[exprn]
+			if exprChk[exprn] == exprtoken { /* valid shift */
+				exprrcvr.char = -1
+				exprtoken = -1
+				exprVAL = exprrcvr.lval
+				exprstate = exprn
+				if Errflag > 0 {
+					Errflag--
+				}
+				__goto_x = __goto_exprstack
+				continue Loop
+			}
+
+			__goto_x = __goto_exprdefault
+			continue Loop
+
+		case __goto_exprdefault:
+			/* default state action */
+			exprn = exprDef[exprstate]
+			if exprn == -2 {
+				if exprrcvr.char < 0 {
+					exprrcvr.char, exprtoken = exprlex1(exprlex, &exprrcvr.lval)
+				}
+
+				/* look through exception table */
+				xi := 0
+				for {
+					if exprExca[xi+0] == -1 && exprExca[xi+1] == exprstate {
+						break
+					}
+					xi += 2
+				}
+				for xi += 2; ; xi += 2 {
+					exprn = exprExca[xi+0]
+					if exprn < 0 || exprn == exprtoken {
+						break
+					}
+				}
+				exprn = exprExca[xi+1]
+				if exprn < 0 {
+					// Make sure we report no lookahead when not parsing.
+					exprstate = -1
+					exprrcvr.char = -1
+					exprtoken = -1
+
+					return 0
+				}
+			}
+			if exprn == 0 {
+				/* error ... attempt to resume parsing */
+				switch Errflag {
+				case 0, 1, 2: /* incompletely recovered error ... try again */
+					if Errflag == 0 {
+						exprlex.Error(exprErrorMessage(exprstate, exprtoken))
+						Nerrs++
+						if exprDebug >= 1 {
+							println(exprStatname(exprstate) + " saw " + exprTokname(exprtoken))
+						}
+					}
+					Errflag = 3
+
+					/* find a state where "error" is a legal shift action */
+					for exprp >= 0 {
+						exprn = exprPact[exprS[exprp].yys] + exprErrCode
+						if exprn >= 0 && exprn < exprLast {
+							exprstate = exprAct[exprn] /* simulate a shift of "error" */
+							if exprChk[exprstate] == exprErrCode {
+								__goto_x = __goto_exprstack
+								continue Loop
+							}
+						}
+
+						/* the current p has no shift on "error", pop stack */
+						if exprDebug >= 2 {
+							println("error recovery pops state " + __yystrconv__.Itoa(exprS[exprp].yys))
+						}
+						exprp--
+					}
+
+					// Make sure we report no lookahead when not parsing.
+					exprstate = -1
+					exprrcvr.char = -1
+					exprtoken = -1
+
+					/* there is no state on the stack with an error shift ... abort */
+					return 1
+
+				case 3: /* no shift yet; clobber input char */
+					if exprDebug >= 2 {
+						println("error recovery discards " + exprTokname(exprtoken))
+					}
+					if exprtoken == exprEofCode {
+						// Make sure we report no lookahead when not parsing.
+						exprstate = -1
+						exprrcvr.char = -1
+						exprtoken = -1
+
+						return 1
+					}
+					exprrcvr.char = -1
+					exprtoken = -1
+
+					__goto_x = __goto_exprnewstate /* try again in the same state */
+					continue Loop
+				}
+			}
+
+			/* reduction by production exprn */
+			if exprDebug >= 2 {
+				println("reduce " + __yystrconv__.Itoa(exprn) + " in:")
+				println("\t" + exprStatname(exprstate))
+			}
+
+			exprnt := exprn
+			exprpt := exprp
+			_ = exprpt // guard against "declared and not used"
+
+			exprp -= exprR2[exprn]
+			// exprp is now the index of $0. Perform the default action. Iff the
+			// reduced production is ε, $1 is possibly out of range.
+			if exprp+1 >= len(exprS) {
+				nyys := make([]exprSymType, len(exprS)*2)
+				for i := 0; i < len(exprS); i++ {
+					nyys[i] = exprS[i]
+				}
+				exprS = nyys
+			}
+			exprVAL = exprS[exprp+1]
+
+			/* consult goto table to find next state */
+			exprn = exprR1[exprn]
+			exprg := exprPgo[exprn]
+			exprj := exprg + exprS[exprp].yys + 1
+
+			if exprj >= exprLast {
+				exprstate = exprAct[exprg]
+			} else {
+				exprstate = exprAct[exprj]
+				if exprChk[exprstate] != -exprn {
+					exprstate = exprAct[exprg]
+				}
+			}
+			// dummy call; replaced with literal code
+			switch exprnt {
+
+			case 1:
+				exprDollar = exprS[exprpt-1 : exprpt+1]
+				{
+					println(exprDollar[1].num)
+				}
+			case 3:
+				exprDollar = exprS[exprpt-2 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[2].num
+				}
+			case 4:
+				exprDollar = exprS[exprpt-2 : exprpt+1]
+				{
+					exprVAL.num = -exprDollar[2].num
+				}
+			case 6:
+				exprDollar = exprS[exprpt-3 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[1].num + exprDollar[3].num
+				}
+			case 7:
+				exprDollar = exprS[exprpt-3 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[1].num - exprDollar[3].num
+				}
+			case 9:
+				exprDollar = exprS[exprpt-3 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[1].num * exprDollar[3].num
+				}
+			case 10:
+				exprDollar = exprS[exprpt-3 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[1].num / exprDollar[3].num
+				}
+			case 12:
+				exprDollar = exprS[exprpt-3 : exprpt+1]
+				{
+					exprVAL.num = exprDollar[2].num
+				}
+			}
+
+			__goto_x = __goto_exprstack /* stack new state and value */
+			continue Loop
+
+		} // switch
+	} // for
+}
diff --git a/internal/app/yacc/yacc.go b/internal/app/yacc/yacc.go
index bf4306c..db59e49 100644
--- a/internal/app/yacc/yacc.go
+++ b/internal/app/yacc/yacc.go
@@ -408,7 +408,7 @@ func setup() {
 		fmt.Fprintf(ftable, "%s\n\n", strings.TrimSpace(copyright))
 	}
 
-	fmt.Fprintf(ftable, "// Code generated by 'wa yacc %s'. DO NOT EDIT.\n", strings.Join(os.Args[1:], " "))
+	fmt.Fprintf(ftable, "// Code generated by 'wa yacc %s'. DO NOT EDIT.\n\n", strings.Join(os.Args[1:], " "))
 
 	defin(0, "$end")
 	extval = PRIVATE // tokens start in unicode 'private use'