nrform

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 代码 · 共 156 行

block data
integer cshift, csize, yynlin
common /yyllib/ cshift, csize, yynlin
data yynlin/YYNEWLINE/
end
block data
common /yyldat/ yyfnd, ymorf, yyprev, yybgin, yytop
integer yyfnd, yymorf, yyprev, yybgin, yytop
data yybgin/1/
data yyprev/YYNEWLINE/
data yytop/YYTOPVAL/
end
integer function yylook(dummy)
common /Lverif/ verif
common /Ladvan/ advan
common /Lstoff/ stoff
common /Lsfall/ sfall
common /Latable/ atable
common /Lextra/ extra
common /Lvstop/ vstop
integer verif(Sverif), advan(Sadvan),stoff(Sstoff),match(Smatch)
integer sfall(Ssfall),atable(Satable),extra(Sextra), vstop(Svstop)
integer state, lsp, r
integer  ch, n
common /yyldat/ yyfnd, yymorf, yyprev, yybgin, yytop, yylsp, yylsta(YYLMAX)
common /yyxel/ yyleng, yytext
integer yyfnd, yymorf, yylsta, yylsp, yytext, yyprev, yyleng, yytop
integer  lexshf, yytext(YYLMAX), yyback, yybgin
integer z, t
if (yymorf .eq. 0)
	yyleng = 0
else
	yymorf=0
1776
	lsp = 1
	state = yybgin
	if (yyprev .eq. YYNEWLINE)
		state = state + 1
	for (;;){
		r = stoff(state)
		if (r .eq. 0){
			z = sfall(state)
			if (z .eq. 0)
				break
			if(stoff(z) == 0) break
			}
		ch = input(dummy)
		ich = lexshf(ch)
		yyleng = yyleng+1
		yytext(yyleng) = ch
		1984
		if(r .gt. 0){
			t = r + ich
			if (t<= yytop){
			  if (verif(t) .eq. state){
				if(advan(t) == YYERROR){
					call unput(yytext(yyleng))
					yyleng = yyleng - 1
					break
					}
				state = advan(t)
				yylsta(lsp) = state
				lsp = lsp +1
				goto 2001
				}
			  }
			}
		if(r < 0){
			t = r + ich
			if (t <= yytop .and. verif(t) .eq. state){
				if(advan(t) == YYERROR){
					call unput(yytext(yyleng))
					yyleng = yyleng - 1
					break
					}
				state = advan(t)
				yylsta(lsp) = state
				lsp = lsp +1
				goto 2001
				}
			t = r + match(ich)
			if(t <= yytop && state == verif(t)){
				if(advan(t) == YYERROR){
					call unput(yytext(yyleng))
					yyleng = yyleng - 1
					break
					}
			state = advan(t)
			yylsta(lsp) = state
			lsp = lsp + 1
			goto 2001
			}
		}
		else {
			if (state > 0) state = sfall(state)
			if (state .gt. 0) r = stoff(state)
			if (state .gt. 0 .and. r .ne. 0)
				goto 1984
			call unput(yytext(yyleng))
			yyleng = yyleng -1
			break
			}
	2001
		continue
		}
	while (lsp .gt. 1){
		lsp = lsp -1
		ilsp = yylsta(lsp)
		yyfnd = atable(ilsp)
		if (yyfnd .gt. 0)
			if (vstop(yyfnd) .gt. 0){
				r = vstop(yyfnd)
				if (extra(r) .ne. 0){
					for(;;){
					ilsp = yylsta(lsp)
					if (yyback(atable(ilsp), -r) .eq. 1)
						break
					lsp= lsp -1
					call unput(yytext(yyleng))
					yyleng = yyleng -1
					}
					}
				yyprev = lexshf(yytext(yyleng))
				yylsp = lsp
				yyfnd = yyfnd + 1
				yylook = r
				yytext(yyleng+1) = 0
				return
				}
		call unput(yytext(yyleng))
		}
	if (yytext(1) .eq. 0){
		yylook=0
		return
		}
	yyprev = input(dummy)
	call output(yyprev)
	yyprev = lexshf(yyprev)
	yyleng = 0
	goto 1776
end
integer function yyback (isub, n)
common /Lvstop/ vstop
integer vstop(Svstop)
if (isub .ne. 0)
while (vstop(isub) .ne. 0){
	if (vstop(isub) .eq. m){
		yyback = 1
		return
		}
	isub = isub + 1
	}
yyback = 0
return 
end