FLEX - 正則表達式 - AWK中的匹配評論

Question

我正在研究掃描文件並突出顯示（g）awk標記的程序。 Flex用於爲（g）awk生成詞法分析器掃描程序。

我的問題：我沒有經驗爲Flex編寫正則表達式。現在我無法弄清楚如何生成匹配整個評論的正則表達式。看到下面的示例.awk程序將被掃描：

#!/usr/bin/awk -f 
############################################################################### 
# 
# @(#) solve.awk - sudoku solver in awk using efficient backtracking algorithm 
# @(#) $Id: solve.awk,v 1.16 2008/03/24 04:04:44 bduncan Exp bduncan $ 
# @(#) Copyright (C) 2005-2008, Bill Duncan, <bduncan-sudoku@beachnet.org> 
# 
# License: 
# This program is free software: you can redistribute it and/or modify 
# it under the terms of the GNU General Public License as published by 
# the Free Software Foundation, either version 3 of the License, or 
# (at your option) any later version. 
# 
# This program is distributed in the hope that it will be useful, 
# but WITHOUT ANY WARRANTY; without even the implied warranty of 
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
# GNU General Public License for more details. 
# 
# You should have received a copy of the GNU General Public License 
# along with this program. If not, see http://www.gnu.org/licenses/. 
# 
# Description: 
# - uses simple recursive backtracking algorithm with up-front and 
# ongoing elimination of invalid tries by tracking for each row, 
# column and region.. 
# 
# Notes: 
# - precalc of regmap didn't seem to make a difference 
# - removed unmark() function and added a parameter to mark() 
# 
# Variables: 
# regmap[r,c] ; pre-compiled, which region sector is r,c 
# master[r,c] ; master matrix 
# C[col, elem] ; true if elem in Column 
# R[row, elem] ; true if elem in Row 
# Q[reg, elem] ; true if elem in Region (Quadrant) 
# 
############################################################################### 
BEGIN { 
SUBSEP = "," # so we can dump and it looks nice 
ORDER = 9 
DEBUG = 0 
count = 0 
# precompile region map for faster lookup 
# for (i = 0; i < ORDER; i++) 
# for (j = 0; j < ORDER; j++) 
# regmap[i+1,j+1] = int(i/3)*3+int(j/3)+1 
} 
function dump(i,j) { 
printf "\n" 
for (i=1;i<=ORDER;i++) { 
if (!((i-1)%3)) printf "\n" 
for (j=1;j<=ORDER;j++) { 
if (!((j-1)%3)) printf " " 
printf " %1d",master[i,j] 
} 
printf "\n" 
} 
printf "\n" 
} 
function fregmap(r,c) { 
# return regmap[r,c] 
return int((r-1)/3)*3+int((c-1)/3)+1 
} 
function inuse(r,c,try) { 
# q = fregmap(r,c) 
# can we use it or is it in use? returns true if already used, not avail 
return (C[c,try] || R[r,try] || Q[fregmap(r,c),try]) 
} 
function mark(r,c,try, flag, q) { 
q = fregmap(r,c) 
Q[q,try] = flag 
R[r,try] = flag 
C[c,try] = flag 
master[r,c] = flag ? try : 0 
} 
function search(r,c, q,i,a,try) { 
# find the next empty slot from here r,c 
# if we've reached the end (no more empty) do check? 
# for each available number, recurse search 
count++ 
while (master[r,c]) { 
if (++c > ORDER) { 
c = 1 
if (++r > ORDER) { 
# then we're done filling! return goodness 
return 1 
} 
} 
} 
# for each of the available numbers for this slot 
for (try=1; try <= ORDER; try++) { 
if (! inuse(r,c,try)) { 
mark(r,c,try, 1) 
if (search(r,c)) return 1 
# else zero returned -- unwind 
mark(r,c,try, 0) # unmark 
} 
} 
return 0 
} 
############ 
# PATTERNS # 
############ 
NF == 0 { next } 
$1 ~ /^#/ { next } 
NF != ORDER { 
printf "error on line %d, NF=%d\n", FNR, NF 
exit 1 
} 
{ 
++row 
for (col=1; col <= ORDER; col++) { 
mark(row,col,$col, 1) 
} 
} 
END { 
search(1,1) 
printf "\n# Searches=%d\n", count 
dump() 
} 

我目前使用「^＃+」來匹配評論。這匹配所有的「＃」字符，但它不匹配該行中其餘的字符。如何匹配「＃」後的所有內容？

Flex模式結構可以回顧in the Flex manual。

Answer 1

的+修飾符意味着「一個或多個先前圖案的」，這是字面#，所以這僅匹配包含一個或多個連續的散列從塔1

開始對於一個行的起始部固定匹配（線的開始），你將需要：

^#.* 

AFAICR，該.不匹配換行符。這意味着一行以#開頭，後跟零個或多個任何類型的其他字符（除了換行符）。

不要忘記，awk意見不限制在一行的開頭開始：

awk '{ 
     # This comment is indented by a number of spaces 
     print $1; # And this is preceded by a command 
    }' 

在廣泛的範圍，你遇到一個#任何時候，這是一個註釋的開始。該限制排除字符串和正則表達式的機構：

awk '{ print "# Not a comment" }' 

awk '/#.*/ { print "Line contains a # comment: ", $0; }' 

等，所以，你需要你的正則表達式規則，字符串規則踢在註釋規則不前。