Catch an entire function with grep - bash

Question

In want to replace a function in a file by another. I have this :
File1.cpp:
void Component::initialize()
{
my_component = new ComponentClass();
}
and File2.cpp:
void Component::initialize()
{
if (doInit)
{
my_component = new ComponentClass();
}
else
{
my_component.ptr = null;
}
}
I've try to write a script but my grep does not provide a result :
Old=$(grep -Eo "void Component::initialize(\n|.)*(^})*?" file1.cpp)
echo "Old=$Old" # empty variable
# My purpose is to do this :
New=$(grep -Eo "void Component::initialize(\n|.)*(^})*?" file2.cpp)
sed -i "s/$Old/$New/g" file1.cpp

Answer 1

#!/usr/bin/awk -f
/^void Component::initialize\(\)$/ {
temp = $0
while (!/^}/ && getline > 0)
temp = temp ORS $0
if (NR == FNR) {
new = temp
nextfile
}
$0 = new
}
NR != FNR
Usage:
awk -f script.awk file{2,1}.cpp

Answer 2

Here is a grep-centric bash script solution (since these are what the OP mentioned explicitly):
Mac_3.2.57$cat replaceFunc.sh
#!/bin/bash
# presumes code has been lint'd into consistent format
oldFile=$1
newFile=$2
# find line # (oldFuncLineNum) of "void Component::initialize()" line
oldFuncLineNum=`cat $oldFile | grep -n '^void Component::initialize()$' | cut -c 1`
# find line # (oldSquiglyLineNum) of first "}" line after oldFuncLineNum
oldSquiglyLineNum=1
while [ $oldSquiglyLineNum -lt $oldFuncLineNum ]
do
found=0
while [ $found -eq 0 ]
do
oldSquiglyLineNum=`expr $oldSquiglyLineNum + 1`
head -n $oldSquiglyLineNum $oldFile | tail -n 1 | grep '^}$' > /dev/null
found=`test ! -f $? && echo "1" || echo "0"`
done
done
oldTotSize=`sed -n '$=' $oldFile`
oldTailSize=`expr $oldTotSize - $oldSquiglyLineNum`
#echo "got: oldFuncLineNum = $oldFuncLineNum"
#echo "got: oldSquiglyLineNum = $oldSquiglyLineNum"
#echo "got oldTotSize = $oldTotSize"
#echo "oldTailSize = $oldTailSize"
# find line # (newFuncLineNum) of "void Component::initialize()" line
newFuncLineNum=`cat $newFile | grep -n '^void Component::initialize()$' | cut -c 1`
# find line # (newSquiglyLineNum) of first "}" line after newFuncLineNum
newSquiglyLineNum=1
while [ $newSquiglyLineNum -lt $newFuncLineNum ]
do
found=0
while [ $found -eq 0 ]
do
newSquiglyLineNum=`expr $newSquiglyLineNum + 1`
head -n $newSquiglyLineNum $newFile | tail -n 1 | grep '^}$' > /dev/null
found=`test ! -f $? && echo "1" || echo "0"`
done
done
newDelta=`expr $newSquiglyLineNum - $newFuncLineNum`
#echo "got: newFuncLineNum = $newFuncLineNum"
#echo "got: newSquiglyLineNum = $newSquiglyLineNum"
#echo "got: newDelta = $newDelta"
# Display oldFile up to the function:
cat $oldFile | head -n $oldFuncLineNum
# ... followed by the new function:
cat $newFile | head -n $newSquiglyLineNum | tail -n $newDelta
# ... followed by the remaining portion of the oldFile:
cat $oldFile | tail -n $oldTailSize
exit 0
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$cat File1.cpp
blah blah
blah
void Component::initialize()
{
my_component = new ComponentClass();
}
blab blab blab
...
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$cat File2.cpp
yaddy yadda
yaddy yadda
void Component::initialize()
{
if (doInit)
{
my_component = new ComponentClass();
}
else
{
my_component.ptr = null;
}
}
blah
blah
blab blab blab
...
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$
Mac_3.2.57$./replaceFunc.sh File1.cpp File2.cpp
blah blah
blah
void Component::initialize()
{
if (doInit)
{
my_component = new ComponentClass();
}
else
{
my_component.ptr = null;
}
}
blab blab blab
...
Mac_3.2.57$

Answer 3

Circling back with a working solution to my original non-functional answer (now deleted).
I managed to work thru the issue with the original defective sed script posted on linuxtopia, and was able to get the generic solution I was looking for. That is given as an answer here.