renames

string_algorithms.cc

@@ -0,0 +1,169 @@
+static_assert( __cplusplus > 2020'00 );
+
+#include "string_algorithms.h"
+
+#include <memory>
+#include <algorithm>
+#include <exception>
+
+#include "error.h"
+#include "AutoRAII.h"
+
+namespace Alepha::Hydrogen  ::detail::  string_algorithms
+{
+	namespace
+	{
+		namespace C
+		{
+			const bool debug= false;
+			const bool debugExpansion= false or C::debug;
+			const bool debugCommas= false or C::debug;
+			const bool debugIOStreamLifecycle= false or C::debug;
+		}
+
+		struct VariableExpansionStreambuf
+			: public Utility::StackableStreambuf
+		{
+			public:
+				VarMap substitutions;
+				std::stringbuf varName;
+				char sigil;
+				enum { Symbol= 1, Normal= 0 } mode= Normal;
+				int throws= 0;
+
+				explicit
+				VariableExpansionStreambuf( std::ostream &os, VarMap &&substitutions, const char sigil )
+					: StackableStreambuf( os ), substitutions( std::move( substitutions ) ), sigil( sigil )
+				{}
+
+				void
+				writeChar( const char ch ) override
+				{
+					std::ostream current{ underlying };
+
+					if( mode == Normal and ch == sigil )
+					{
+						mode= Symbol;
+						varName.str( "" );
+						return;
+					}
+					if( mode == Symbol and ch == sigil )
+					{
+						mode= Normal;
+						const std::string name( varName.view() );
+						if( not name.empty() )
+						{
+							if( not substitutions.contains( name ) )
+							{
+								throw std::runtime_error{ "No such variable: `" + name +"`" };
+							}
+							if( C::debugExpansion ) error() << "Expanding variable with name `" << name << "`" << std::endl;
+							current << substitutions.at( name )();
+						}
+						else current << sigil;
+						return;
+					}
+
+					if( mode == Symbol ) current.rdbuf( &varName );
+					current << ch;
+				}
+
+				void
+				drain()
+				{
+					if( C::debugIOStreamLifecycle ) error() << "Drain called, and mode is: " << mode << std::endl;
+					if( mode != Normal )
+					{
+						if( C::debugIOStreamLifecycle ) error() << "Mode not being normal, we're throwing (" << ++throws << " times now)..." << std::endl;
+						mode= Normal;
+						throw std::runtime_error{ "Unterminated variable `" + varName.str() + " in expansion." };
+					}
+				}
+		};
+	}
+
+	void
+	impl::build_streambuf( std::ostream &os, StartSubstitutions &&params )
+	{
+		new VariableExpansionStreambuf{ os, std::move( params.substitutions ), params.sigil };
+	}
+
+	std::string
+	exports::expandVariables( const std::string &text, const VarMap &vars, const char sigil )
+	{
+		std::ostringstream oss;
+
+		oss << StartSubstitutions{ sigil, vars };
+		oss << text;
+		oss << EndSubstitutions;
+
+		return std::move( oss ).str();
+	}
+
+	std::vector< std::string >
+	exports::parseCommas( const std::string &string )
+	{
+		enum { Text, Backslash } state= Text;
+
+		std::vector< std::string > rv;
+		std::string next;
+		for( const char ch: string )
+		{
+			if( state == Backslash )
+			{
+				state= Text;
+				next+= ch;
+			}
+			else if( state == Text )
+			{
+				if( ch == '\\' ) state= Backslash;
+				else if( ch == ',' )
+				{
+					if( C::debugCommas ) error() << "Parsed from commas: `" << next << "`" << std::endl;
+					rv.push_back( std::move( next ) );
+					next.clear();
+				}
+				else next+= ch;
+			}
+		}
+
+		if( C::debugCommas ) error() << "Final parsed from commas: `" << next << "`" << std::endl;
+		rv.push_back( std::move( next ) );
+
+		return rv;
+	}
+
+	std::vector< std::string >
+	exports::split( const std::string &s, const char token )
+	{
+		std::vector< std::string > rv;
+		std::string next;
+		for( const char ch: s )
+		{
+			if( ch != token )
+			{
+				next+= ch;
+				continue;
+			}
+			rv.push_back( std::move( next ) );
+			next.clear();
+		}
+		rv.push_back( std::move( next ) );
+		return rv;
+	}
+
+	std::vector< std::string >
+	exports::split( std::string s, const std::string &delim )
+	{
+		std::vector< std::string > rv;
+		while( true )
+		{
+			const auto pos= s.find( delim );
+			rv.push_back( s.substr( 0, pos ) );
+			if( pos == std::string::npos ) break;
+			s= s.substr( pos + delim.size() );
+		}
+
+		return rv;
+	}
+}