Remove To_String by using AST->to_string and inspect

[mgreter]

This cleans up the usage of perform(&to_string) by only using inspect. Also adding additional TO_SASS output mode, since ruby sass has differences between to_sass and inspect and both are used in various places (i.e. error reporting). Now every AST_Node has a to_string, to_sass and inspect method, and all return a std::string. They all internaly use the inspect visitors, so we only need to implement all types only once for all variations in one place. With this I hope we can more easily match ruby sass and I already saw one or two things that need to be implemented for certain options. The to_sass mode specially is responsible to add parentheses were needed.

This is basically the continuation of #1754

[mgreter]

@xzyfer I'm thinking about renaming Inspect visitor class to Stringify, because the name is IMO a bit confusing, since it handles all the stringification now. In terms of ruby sass it never did what ruby sass internaly does with inspect. We should use to_string, to_sass and inspect methods on AST_Node instances. These correspond to ruby sass perform, #{node.to_sass(opts)} and #{node.inspect}.

I also want to add an emitter that does not create a sourcemap, since for these methods it's not necesarry (but that's really just a performance optimization). Things start to come together.

[xzyfer]

@mgreter Ruby Sass calls it the ToCss visitor. Seems like an ideal name to me?

[xzyfer]

Now every AST_Node has a to_string, to_sass and inspect method, and all return a std::string.

This is a great change. I wasn't expecting to implement this until 3.4. Nice work.

[saper]

I am getting this now:

gmake BUILD=debug-shared CC=cc CXX=c++
mkdir lib
cc -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/cencode.o src/cencode.c
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/ast.o src/ast.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/base64vlq.o src/base64vlq.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/bind.o src/bind.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/color_maps.o src/color_maps.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/constants.o src/constants.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/context.o src/context.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/cssize.o src/cssize.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/emitter.o src/emitter.cpp
c++ -g -DDEBUG -DDEBUG_LVL="NONE" -Wall -DLIBSASS_VERSION=""3.3.3-19-g3054"" -std=c++0x -I /home/saper/sw/libsass/include -fPIC -fPIC -c -o src/environment.o src/environment.cpp
src/environment.cpp:183:38: error: no matching member function for call to 'to_string'
{ std::cerr << " : " << val->to_string(true, 5); }
~~~~~^~~~~~~~~
src/ast.hpp:94:25: note: candidate function not viable: requires single argument 'opt', but 2 arguments were
provided
virtual std::string to_string(Sass_Inspect_Options opt) const;
^
src/ast.hpp:95:25: note: candidate function not viable: requires 0 arguments, but 2 were provided
virtual std::string to_string() const;
^
1 error generated.

is it because of this change?

[xzyfer]

@saper is that error still happening on b6841ed? I'm unable to reproduce.

[saper]

Yes, see #1917 (comment)