diff --git a/builtin.cpp b/builtin.cpp
index f30d842e9..a3f4ebe13 100644
--- a/builtin.cpp
+++ b/builtin.cpp
@@ -3929,7 +3929,7 @@ void builtin_push_io( parser_t &parser, int in )
 	sb_init( sb_err );
 }
 
-void builtin_pop_io()
+void builtin_pop_io(parser_t &parser)
 {
 	builtin_stdin = 0;
 	sb_destroy( sb_out );
diff --git a/builtin.h b/builtin.h
index e14bdc72c..fead6e25a 100644
--- a/builtin.h
+++ b/builtin.h
@@ -165,7 +165,7 @@ const wchar_t *builtin_get_desc( const wchar_t *b );
    the commandline builtin operate on the string to complete instead
    of operating on whatever is to be completed.
 */
-const wchar_t *builtin_complete_get_temporary_buffer(parser_t &parser);
+const wchar_t *builtin_complete_get_temporary_buffer();
 
 
 /**
diff --git a/builtin_commandline.cpp b/builtin_commandline.cpp
index 2615db733..0ead09949 100644
--- a/builtin_commandline.cpp
+++ b/builtin_commandline.cpp
@@ -232,7 +232,7 @@ static int builtin_commandline( parser_t &parser, wchar_t **argv )
 	int search_mode = 0;
 	wchar_t *begin, *end;
 
-	current_buffer = (wchar_t *)builtin_complete_get_temporary_buffer(parser);
+	current_buffer = (wchar_t *)builtin_complete_get_temporary_buffer();
 	if( current_buffer )
 	{
 		current_cursor_pos = wcslen( current_buffer );
diff --git a/event.cpp b/event.cpp
index efc3de501..b08856245 100644
--- a/event.cpp
+++ b/event.cpp
@@ -173,7 +173,7 @@ static int event_is_blocked( event_t *e )
 {
 	block_t *block;
 	event_block_t *eb;
-	
+	parser_t &parser = parser_t::principal_parser();
 	for( block = parser.current_block; block; block = block->outer )
 	{
 		for( eb = block->first_event_block; eb; eb=eb->next )
@@ -184,7 +184,7 @@ static int event_is_blocked( event_t *e )
 				return 1;
 		}
 	}
-	for( eb = global_event_block; eb; eb=eb->next )
+	for( eb = parser.global_event_block; eb; eb=eb->next )
 	{
 		if( eb->type & (1<<EVENT_ANY ) )
 			return 1;
@@ -459,6 +459,7 @@ static void event_fire_internal( event_t *event )
 		*/
 		proc_push_interactive(0);
 		prev_status = proc_get_last_status();
+        parser_t &parser = parser_t::principal_parser();
 		parser.push_block( EVENT );
 		parser.current_block->param1.event = event;
 		parser.eval( buffer.c_str(), 0, TOP );
diff --git a/expand.cpp b/expand.cpp
index 561bdfba8..ff62d540a 100644
--- a/expand.cpp
+++ b/expand.cpp
@@ -1766,8 +1766,9 @@ static void remove_internal_separator2( wcstring &s, int conv )
 }
 
 
-int expand_string2( parser_t &parser, const wcstring &input, std::vector<wcstring> &output, int flags )
+int expand_string2( const wcstring &input, std::vector<wcstring> &output, int flags )
 {
+    parser_t &parser = parser_t::principal_parser();
     std::vector<wcstring> list1, list2;
 	std::vector<wcstring> *in, *out;
     
@@ -1985,14 +1986,14 @@ int expand_string2( parser_t &parser, const wcstring &input, std::vector<wcstrin
 /**
    The real expansion function. expand_one is just a wrapper around this one.
 */
-int expand_string( parser_t &parser,
-                   void *context,
+int expand_string( void *context,
 				   wchar_t *str,
 				   array_list_t *end_out,
 				   int flags )
 {
 	array_list_t list1, list2;
 	array_list_t *in, *out;
+    parser_t &parser = parser_t::principal_parser();
 
 	int i;
 	int cmdsubst_ok = 1;
diff --git a/fish.cpp b/fish.cpp
index b37192b9a..6fe9f7a8f 100644
--- a/fish.cpp
+++ b/fish.cpp
@@ -314,11 +314,12 @@ int main( int argc, char **argv )
 	reader_init();
 	history_init();
 
+    parser_t &parser = parser_t::principal_parser();
+
 	if( read_init() )
 	{
 		if( cmd != 0 )
 		{
-            parser_t parser(PARSER_TYPE_GENERAL);
 			wchar_t *cmd_wcs = str2wcs( cmd );
 			res = parser.eval( cmd_wcs, 0, TOP );
 			free(cmd_wcs);
@@ -394,7 +395,7 @@ int main( int argc, char **argv )
 	builtin_destroy();
 	function_destroy();
 	reader_destroy();
-	parser_destroy();
+	parser.destroy();
 	wutil_destroy();
 	event_destroy();
 	
diff --git a/input.cpp b/input.cpp
index e2b207f71..eb4cf202e 100644
--- a/input.cpp
+++ b/input.cpp
@@ -398,7 +398,7 @@ static wint_t input_exec_binding( const input_mapping_t &m, const wcstring &seq
 		*/
 		int last_status = proc_get_last_status();
 	  		
-		eval( m.command.c_str(), 0, TOP );
+		parser_t::principal_parser().eval( m.command.c_str(), 0, TOP );
 		
 		proc_set_last_status( last_status );
 		
diff --git a/iothread.cpp b/iothread.cpp
index 3f83c9e5e..703fda5e7 100644
--- a/iothread.cpp
+++ b/iothread.cpp
@@ -6,6 +6,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <signal.h>
 
 
 #define VOMIT_ON_FAILURE(a) do { if (0 != (a)) { int err = errno; fprintf(stderr, "%s failed on line %d in file %s: %d (%s)\n", #a, __LINE__, __FILE__, err, strerror(err)); abort(); }} while (0)
@@ -90,6 +91,11 @@ static void *iothread_worker(void *threadPtr) {
 	assert(threadPtr != NULL);
 	struct WorkerThread_t *thread = (struct WorkerThread_t *)threadPtr;
 	
+    // We don't want to receive signals on this thread
+    sigset_t set;
+    sigfillset(&set);
+    VOMIT_ON_FAILURE(pthread_sigmask(SIG_SETMASK, &set, NULL));
+    
 	/* Grab a request off of the queue */
 	struct ThreadedRequest_t *req;
 	VOMIT_ON_FAILURE(pthread_mutex_lock(&s_request_queue_lock));
diff --git a/parser.cpp b/parser.cpp
index f681327db..0969de115 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -397,10 +397,17 @@ static int job_start_pos;
 */
 static int eval_level=-1;
 
-static int parse_job( process_t *p,
-					  job_t *j,
-					  tokenizer *tok );
+parser_t::parser_t(enum parser_type_t type) : parser_type(type)
+{
+    
+}
 
+parser_t &parser_t::principal_parser(void)
+{
+    ASSERT_IS_MAIN_THREAD();
+    static parser_t parser(PARSER_TYPE_GENERAL);
+    return parser;
+}
 
 /**
    Return the current number of block nestings
@@ -462,7 +469,7 @@ void parser_t::push_block( int type )
 	}
 }
 
-void parser_pop_block()
+void parser_t::pop_block()
 {
 	block_t *old = current_block;
 	if( !current_block )
@@ -478,7 +485,7 @@ void parser_pop_block()
 	halloc_free( old );
 }
 
-const wchar_t *parser_get_block_desc( int block )
+const wchar_t *parser_t::get_block_desc( int block ) const
 {
 	int i;
 	
@@ -595,7 +602,7 @@ static const wchar_t *parser_find_end( const wchar_t * buff )
 }
 
 
-void parser_forbid_function( wchar_t *function )
+void parser_t::forbid_function( wchar_t *function )
 {
 /*
   if( function )
@@ -605,7 +612,7 @@ void parser_forbid_function( wchar_t *function )
     forbidden_function.push_back(wcstring(function));
 }
 
-void parser_allow_function()
+void parser_t::allow_function()
 {
 /*
   if( al_peek( &forbidden_function) )
@@ -880,7 +887,7 @@ int parser_t::eval_args( const wchar_t *line, array_list_t *args )
 	return 1;
 }
 
-void parser_stack_trace( block_t *b, string_buffer_t *buff)
+void parser_t::stack_trace( block_t *b, string_buffer_t *buff)
 {
 	
 	/*
@@ -980,7 +987,7 @@ void parser_stack_trace( block_t *b, string_buffer_t *buff)
 	/*
 	  Recursively print the next block
 	*/
-	parser_stack_trace( b->outer, buff );
+	parser_t::stack_trace( b->outer, buff );
 }
 
 /**
@@ -1007,7 +1014,7 @@ static const wchar_t *is_function()
 }
 
 
-int parser_get_lineno()
+int parser_t::get_lineno() const
 {
 	const wchar_t *whole_str;
 	const wchar_t *function_name;
@@ -1036,7 +1043,7 @@ int parser_get_lineno()
 	return lineno;
 }
 
-const wchar_t *parser_current_filename()
+const wchar_t *parser_t::current_filename() const
 {
 	block_t *b = current_block;
 
@@ -1101,7 +1108,7 @@ const wchar_t *parser_t::current_line()
 		return L"";
 	}
 
-	file = parser_current_filename();
+	file = parser_t::current_filename();
 	whole_str = tok_string( current_tokenizer );
 	line = whole_str;
 
@@ -1196,34 +1203,34 @@ const wchar_t *parser_t::current_line()
 	}
 
 	free( line );
-	parser_stack_trace( current_block, lineinfo );
+	parser_t::stack_trace( current_block, lineinfo );
 
 	return (wchar_t *)lineinfo->buff;
 }
 
-int parser_get_pos()
+int parser_t::get_pos() const
 {
 	return tok_get_pos( current_tokenizer );
 }
 
-int parser_get_job_pos()
+int parser_t::get_job_pos() const
 {
 	return job_start_pos;
 }
 
 
-void parser_set_pos( int p)
+void parser_t::set_pos( int p)
 {
 	tok_set_pos( current_tokenizer, p );
 }
 
-const wchar_t *parser_get_buffer()
+const wchar_t *parser_t::get_buffer() const
 {
 	return tok_string( current_tokenizer );
 }
 
 
-int parser_is_help( wchar_t *s, int min_match )
+int parser_t::is_help( wchar_t *s, int min_match ) const
 {
 	int len;
 
@@ -1360,7 +1367,7 @@ void parser_t::parse_job_argument_list( process_t *p,
 				{
 					if( ( proc_is_count ) &&
 					    ( al_get_count( args) == 1) &&
-					    ( parser_is_help( tok_last(tok), 0) ) &&
+					    ( parser_t::is_help( tok_last(tok), 0) ) &&
 					    ( p->type == INTERNAL_BUILTIN ) )
 					{
 						/*
@@ -2143,7 +2150,7 @@ int parser_t::parse_job( process_t *p,
 
 				while( prev_block != current_block )
 				{
-					parser_pop_block();
+					parser_t::pop_block();
 				}
 
 			}
@@ -2181,7 +2188,7 @@ int parser_t::parse_job( process_t *p,
 		*/
 		while( prev_block != current_block )
 		{
-			parser_pop_block();
+			parser_t::pop_block();
 		}
 	}
 	current_tokenizer_pos = prev_tokenizer_pos;	
@@ -2218,7 +2225,7 @@ void parser_t::skipped_exec( job_t * j )
 					exec( *this, j );
 					return;
 				}
-				parser_pop_block();
+				parser_t::pop_block();
 			}
 			else if( wcscmp( p->argv[0], L"else" )==0)
 			{
@@ -2489,7 +2496,7 @@ int parser_t::eval( const wcstring &cmdStr, io_data_t *io, enum block_type_t blo
 	{
 		debug( 1,
 			   INVALID_SCOPE_ERR_MSG,
-			   parser_get_block_desc( block_type ) );
+			   parser_t::get_block_desc( block_type ) );
 		bugreport();
 		return 1;
 	}
@@ -2516,7 +2523,7 @@ int parser_t::eval( const wcstring &cmdStr, io_data_t *io, enum block_type_t blo
 
 	int prev_block_type = current_block->type;
 
-	parser_pop_block();
+	parser_t::pop_block();
 
 	while( start_current_block != current_block )
 	{
@@ -2536,7 +2543,7 @@ int parser_t::eval( const wcstring &cmdStr, io_data_t *io, enum block_type_t blo
 			//debug( 2, L"Status %d\n", proc_get_last_status() );
 
 			debug( 1,
-				   L"%ls", parser_get_block_desc( current_block->type ) );
+				   L"%ls", parser_t::get_block_desc( current_block->type ) );
 			debug( 1,
 				   BLOCK_END_ERR_MSG );
 			fwprintf( stderr, L"%ls", parser_t::current_line() );
@@ -2548,7 +2555,7 @@ int parser_t::eval( const wcstring &cmdStr, io_data_t *io, enum block_type_t blo
 
 		}
 		prev_block_type = current_block->type;
-		parser_pop_block();
+		parser_t::pop_block();
 	}
 
 	print_errors_stderr(*this);
@@ -2557,7 +2564,7 @@ int parser_t::eval( const wcstring &cmdStr, io_data_t *io, enum block_type_t blo
 	free( current_tokenizer );
 
     while (forbidden_function.size() > forbid_count)
-		parser_allow_function();
+		parser_t::allow_function();
 
 	/*
 	  Restore previous eval state
@@ -2665,7 +2672,7 @@ int parser_t::parser_test_argument( const wchar_t *arg, string_buffer_t *out, co
 				
 //				debug( 1, L"%ls -> %ls %ls", arg_cpy, subst, tmp.buff );
 	
-				err |= parser_test( subst, 0, out, prefix );
+				err |= parser_t::test( subst, 0, out, prefix );
 				
 				free( subst );
 				free( arg_cpy );
@@ -2732,7 +2739,7 @@ int parser_t::parser_test_argument( const wchar_t *arg, string_buffer_t *out, co
 	
 }
 
-int parser_t::parser_test_args(const  wchar_t * buff,
+int parser_t::test_args(const  wchar_t * buff,
 					 string_buffer_t *out, const wchar_t *prefix )
 {
 	tokenizer tok;
@@ -2806,7 +2813,7 @@ int parser_t::parser_test_args(const  wchar_t * buff,
 	return err;
 }
 
-int parser_t::parser_test( const  wchar_t * buff,
+int parser_t::test( const  wchar_t * buff,
 				 int *block_level, 
 				 string_buffer_t *out,
 				 const wchar_t *prefix )
@@ -3102,7 +3109,7 @@ int parser_t::parser_test( const  wchar_t * buff,
 														wcsdup( tok_last( &tok ) ), 
 														EXPAND_SKIP_CMDSUBST);
 								
-								if( first_arg && parser_is_help( first_arg, 3) )
+								if( first_arg && parser_t::is_help( first_arg, 3) )
 								{
 									is_help = 1;
 								}
@@ -3164,7 +3171,7 @@ int parser_t::parser_test( const  wchar_t * buff,
 														wcsdup( tok_last( &tok ) ), 
 														EXPAND_SKIP_CMDSUBST);
 								
-								if( first_arg && parser_is_help( first_arg, 3 ) ) 
+								if( first_arg && parser_t::is_help( first_arg, 3 ) ) 
 								{
 									is_help = 1;
 								}
diff --git a/parser.h b/parser.h
index 1f57829d3..6ffd89e28 100644
--- a/parser.h
+++ b/parser.h
@@ -214,6 +214,7 @@ struct tokenizer;
 
 class parser_t {
     private:
+    enum parser_type_t parser_type;
     std::vector<block_t> blocks;
     
     /* No copying allowed */
@@ -225,13 +226,14 @@ class parser_t {
     void skipped_exec( job_t * j );
     void eval_job( tokenizer *tok );
     int parser_test_argument( const wchar_t *arg, string_buffer_t *out, const wchar_t *prefix, int offset );
-    int parser_test( const  wchar_t * buff, int *block_level,  string_buffer_t *out, const wchar_t *prefix );
-    int parser_test_args(const  wchar_t * buff, string_buffer_t *out, const wchar_t *prefix );
     void print_errors( string_buffer_t *target, const wchar_t *prefix );
     
     public:
     std::vector<profile_item_t> profile_items;
     
+    /** Get the "principal" parser, whatever that is */
+    static parser_t &principal_parser();
+    
     /** Create a parser of the given type */
     parser_t(enum parser_type_t type);
     
@@ -299,7 +301,7 @@ class parser_t {
     /**
        Set the current position in the latest string of the tokenizer.
     */
-    void set_pos( int p) const;
+    void set_pos( int p);
 
     /**
        Get the string currently parsed
@@ -334,7 +336,7 @@ class parser_t {
        \param out if non-null, any errors in the command will be filled out into this buffer
        \param prefix the prefix string to prepend to each error message written to the \c out buffer
     */
-    int test( const wchar_t * buff, int *block_level, string_buffer_t *out, const wchar_t *prefix ) const;
+    int test( const wchar_t * buff, int *block_level, string_buffer_t *out, const wchar_t *prefix );
 
     /**
        Test if the specified string can be parsed as an argument list,
@@ -342,7 +344,7 @@ class parser_t {
        string contains errors, and the second bit is set if the string
        contains an unclosed block.
     */
-    int test_args( const wchar_t * buff, string_buffer_t *out, const wchar_t *prefix ) const;
+    int test_args( const wchar_t * buff, string_buffer_t *out, const wchar_t *prefix );
 
     /**
        Tell the parser that the specified function may not be run if not
diff --git a/proc.cpp b/proc.cpp
index 938e354bf..b1dc85a5e 100644
--- a/proc.cpp
+++ b/proc.cpp
@@ -452,7 +452,8 @@ static void handle_child_status( pid_t pid, int status )
 		}
 		else
 		{
-			block_t *c = parser.current_block;
+            //PCA INSTANCED_PARSER what is this?
+			block_t *c = NULL;//parser.current_block;
 			if( p && found_proc )
 			{
 				while( c )
diff --git a/reader.cpp b/reader.cpp
index d4d2d16a4..490dce3aa 100644
--- a/reader.cpp
+++ b/reader.cpp
@@ -421,7 +421,8 @@ int reader_exit_forced()
 
 static void reader_repaint()
 {
-	parser_test( data->buff, data->indent, 0, 0 );
+    //PCA INSTANCED_PARSER what is this call for?
+	//parser_test( data->buff, data->indent, 0, 0 );
 	
 	s_write( &data->screen,
 		 data->prompt_buff.c_str(),
@@ -479,7 +480,8 @@ static void reader_kill( wchar_t *begin, int length, int mode, int newv )
 
 void reader_handle_int( int sig )
 {
-	block_t *c = current_block;
+    //PCA INSTANCED_PARSER what is this?
+	block_t *c = NULL;//current_block;
 	
 	if( !is_interactive_read )
 	{
@@ -1255,7 +1257,8 @@ static void run_pager( wchar_t *prefix, int is_quoted, array_list_t *comp )
 	out->next = in;
 	out->fd = 4;
 	
-	eval( (wchar_t *)cmd.buff, out, TOP);
+    parser_t parser(PARSER_TYPE_GENERAL);
+	parser.eval( (wchar_t *)cmd.buff, out, TOP);
 	term_steal();
 
 	io_buffer_read( out );
@@ -2189,7 +2192,7 @@ void set_env_cmd_duration(struct timeval *after, struct timeval *before)
 	}
 }
 
-void reader_run_command( const wchar_t *cmd )
+void reader_run_command( parser_t &parser, const wchar_t *cmd )
 {
 
 	wchar_t *ft;
@@ -2207,7 +2210,7 @@ void reader_run_command( const wchar_t *cmd )
 
 	gettimeofday(&time_before, NULL);
 
-	eval( cmd, 0, TOP );
+	parser.eval( cmd, 0, TOP );
 	job_reap( 1 );
 
 	gettimeofday(&time_after, NULL);
@@ -2227,7 +2230,7 @@ void reader_run_command( const wchar_t *cmd )
 
 int reader_shell_test( wchar_t *b )
 {
-	int res = parser_test( b, 0, 0, 0 );
+	int res = parser_t::principal_parser().test( b, 0, 0, 0 );
 	
 	if( res & PARSER_TEST_ERROR )
 	{
@@ -2239,7 +2242,7 @@ int reader_shell_test( wchar_t *b )
 		
 		s_write( &data->screen, L"", L"", tmp, tmp2, 0 );
 		
-		parser_test( b, 0, &sb, L"fish" );
+		parser_t::principal_parser().test( b, 0, &sb, L"fish" );
 		fwprintf( stderr, L"%ls", sb.buff );
 		sb_destroy( &sb );
 	}
@@ -2515,8 +2518,9 @@ static void handle_end_loop()
 	int job_count=0;
 	int is_breakpoint=0;
 	block_t *b;
-	
-	for( b = current_block; 
+	parser_t &parser = parser_t::principal_parser();
+    
+	for( b = parser.current_block; 
 	     b; 
 	     b = b->outer )
 	{
@@ -2577,7 +2581,8 @@ static int read_i()
 	reader_set_complete_function( &complete );
 	reader_set_highlight_function( &highlight_shell );
 	reader_set_test_function( &reader_shell_test );
-	
+	parser_t &parser = parser_t::principal_parser();
+    
 	data->prev_end_loop=0;
 
 	while( (!data->end_loop) && (!sanity_check()) )
@@ -2609,7 +2614,7 @@ static int read_i()
 			
 			data->buff_pos=data->buff_len=0;
 			data->buff[data->buff_len]=L'\0';
-			reader_run_command( tmp );
+			reader_run_command( parser, tmp );
 			free( tmp );
 			if( data->end_loop)
 			{
@@ -3347,6 +3352,7 @@ int reader_search_mode()
 */
 static int read_ni( int fd, io_data_t *io )
 {
+    parser_t &parser = parser_t::principal_parser();
 	FILE *in_stream;
 	wchar_t *buff=0;
 	buffer_t acc;
@@ -3408,9 +3414,9 @@ static int read_ni( int fd, io_data_t *io )
 			string_buffer_t sb;
 			sb_init( &sb );
 		
-			if( !parser_test( str, 0, &sb, L"fish" ) )
+			if( ! parser.test( str, 0, &sb, L"fish" ) )
 			{
-				eval( str, io, TOP );
+				parser.eval( str, io, TOP );
 			}
 			else
 			{
diff --git a/reader.h b/reader.h
index 1bd500542..138ecbccc 100644
--- a/reader.h
+++ b/reader.h
@@ -14,6 +14,8 @@
 #include "util.h"
 #include "io.h"
 
+class parser_t;
+
 /**
   Read commands from \c fd until encountering EOF
 */