Catch an entire function with grep-CodePudding

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

CodePudding user response：

#!/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

CodePudding user response：

Please bear with me here.

There is a generic approach to solving this which is presented here, in section 4.23.3 .

The below script attempts to incorporate and demonstrate that approach.

#!/bin/bash

DBG=1

###
### Code segment to be replaced
###
file1="File1.cpp"
rm -f "${file1}"
cat >"${file1}" <<"EnDoFiNpUt"
void Component::initialize()
{
    my_component = new ComponentClass();
}
EnDoFiNpUt

test ${DBG} -eq 1 && echo "fence 1"

###
### Code segment to be used as replacement
###
file2="File2.cpp"
rm -f "${file2}"
cat >"${file2}" <<"EnDoFiNpUt"
void Component::initialize()
{
    if (doInit)
    {
        my_component = new ComponentClass();
    }
    else
    {
        my_component.ptr = null;
    }
}
EnDoFiNpUt

test ${DBG} -eq 1 && echo "fence 2"

###
### Create demo input file
###
testfile="Test_INPUT.cpp"
rm -f "${testfile}"
{
    echo "
other code1()
{
    doing other things
    doing more things
    doing extra things
} 
"
    cat "${file1}"

echo "
other code2()
{
    creating other things
    creating more things
    creating extra things
} 
"
} >>"${testfile}"

test ${DBG} -eq 1 && echo "fence 3"

###
### Create editing specification file
###
{
    cat "${file1}"
    echo "----"
    cat "${file2}"
} >findrep.txt

test ${DBG} -eq 1 && echo "fence 4"


###
### sed script to create editing instructions to apply aove editing specification file
###
cat >"blockrep.sed" <<"EnDoFiNpUt"
#SOURCE:    https://www.linuxtopia.org/online_books/linux_tool_guides/the_sed_faq/sedfaq4_013.html
#
# filename: blockrep.sed
#   author: Paolo Bonzini
# Requires:
#    (1) blocks to find and replace, e.g., findrep.txt
#    (2) an input file to be changed, input.file
#
# blockrep.sed creates a second sed script, custom.sed,
# to find the lines above the row of 4 hyphens, globally
# replacing them with the lower block of text. GNU sed
# is recommended but not required for this script.
#
# Loop on the first part, accumulating the `from' text
# into the hold space.
:a
/^----$/! {
   # Escape slashes, backslashes, the final newline and
   # regular expression metacharacters.
   s,[/\[.*],\\&,g
   s/$/\\/
   H
   #
   # Append N cmds needed to maintain the sliding window.
   x
   1 s,^.,s/,
   1! s/^/N\
/
   x
   n
   ba
}
#
# Change the final backslash to a slash to separate the
# two sides of the s command.
x
s,\\$,/,
x
#
# Until EOF, gather the substitution into hold space.
:b
n
s,[/\],\\&,g
$! s/$/\\/
H
$! bb
#
# Start the RHS of the s command without a leading
# newline, add the P/D pair for the sliding window, and
# print the script.
g
s,/\n,/,
s,$,/\
P\
D,p
#---end of script---
EnDoFiNpUt

test ${DBG} -eq 1 && echo "fence 5"


sed --debug -nf blockrep.sed findrep.txt >custom.sed
test ${DBG} -eq 1 && echo "fence 6"

if [ -s custom.sed ]
then
    more custom.sed
    echo -e "\t Hit return to continue ..." >&2
    read k <&2
else
    echo -e "\t Failed to create 'custom.sed'.  Unable to proceed!\n" >&2
    exit 1
fi

testout="Test_OUTPUT.cpp"

sed -f custom.sed "${testfile}" >"${testout}"
test ${DBG} -eq 1 && echo "fence 7"

if [ -s "${testout}" ]
then
    more "${testout}"
else
    echo -e "\t Failed to create '${testout}'.\n" >&2
    exit 1
fi

Unfortunately, what they presented doesn't seem to work. The execution log for the above is as follows:

fence 1
fence 2
fence 3
fence 4
fence 5
sed: file blockrep.sed line 19: unterminated `s' command
fence 6
     Failed to create 'custom.sed'.  Unable to proceed!

Maybe an expert out there can resolve the logic error in the imported blockrep.sed script. That would have broad application and be beneficial for many, including the OP and myself.