diff --git a/debugger/CMakeLists.txt b/debugger/CMakeLists.txt
index 0125950..4904fe2 100644
--- a/debugger/CMakeLists.txt
+++ b/debugger/CMakeLists.txt
@@ -11,11 +11,11 @@ add_custom_command(
 )
 
 add_custom_command(
-	OUTPUT parser.cpp parser.h
-	COMMAND cp "${CMAKE_CURRENT_SOURCE_DIR}/parser.lemon" "parser.lemon"
+	OUTPUT parser.c parser.h
+	COMMAND cp -f "${CMAKE_CURRENT_SOURCE_DIR}/parser.lemon" "parser.lemon"
 	COMMAND lemon parser.lemon
-	COMMAND cp parser.h "${CMAKE_CURRENT_SOURCE_DIR}/"
-	COMMAND cp parser.out "${CMAKE_CURRENT_SOURCE_DIR}/"
+	COMMAND cp -f parser.h "${CMAKE_CURRENT_SOURCE_DIR}/"
+	COMMAND cp -f parser.out "${CMAKE_CURRENT_SOURCE_DIR}/"
 	MAIN_DEPENDENCY parser.lemon
 	DEPENDS commands.h
 )
diff --git a/debugger/lexer.re.cpp b/debugger/lexer.re.cpp
index c2f88ee..2ba4ce1 100644
--- a/debugger/lexer.re.cpp
+++ b/debugger/lexer.re.cpp
@@ -17,6 +17,7 @@ extern "C" {
 	void *ParseAlloc(void *(*mallocProc)(size_t));
 	void ParseFree(void *p, void (*freeProc)(void*));
 	void Parse(void *yyp, int yymajor, uint32_t yyminor, Command *command);
+	void ParseTrace(FILE *TraceFILE, char *zTracePrompt);
 
 }
 
@@ -37,7 +38,7 @@ namespace {
 	uint32_t scan10(const char *begin, const char *end)
 	{
 		return std::accumulate(begin, end, 0, 
-			[](char c, uint32_t value){
+			[](uint32_t value, char c){
 				return value * 10 + c - '0';
 			});
 	}
@@ -45,7 +46,7 @@ namespace {
 	uint32_t scan16(const char *begin, const char *end)
 	{
 		return std::accumulate(begin, end, 0, 
-			[](char c, uint32_t value){
+			[](uint32_t value, char c){
 				return (value << 4) + tox(c);
 			});
 	}
@@ -109,6 +110,8 @@ bool ParseLine(const char *iter, Command *command)
 
 	parser = ParseAlloc(malloc);
 
+	//ParseTrace(stdout, "--> ");
+
 	for (;;)
 	{
 		const char *begin = iter;
@@ -125,42 +128,42 @@ bool ParseLine(const char *iter, Command *command)
 			continue;
 		}
 
-		'>=' { Parse(&parser, tkGTEQ, 0, command); continue; }
-		'>>' { Parse(&parser, tkGTGT, 0, command); continue; }
-		'<=' { Parse(&parser, tkLTEQ, 0, command); continue; }
-		'<<' { Parse(&parser, tkLTLT, 0, command); continue; }
-		'!=' { Parse(&parser, tkBANGEQ, 0, command); continue; }
-		'==' { Parse(&parser, tkEQEQ, 0, command); continue; }
-		'||' { Parse(&parser, tkPIPEPIPE, 0, command); continue; }
-		'&&' { Parse(&parser, tkAMPAMP, 0, command); continue; }
+		'>=' { Parse(parser, tkGTEQ, 0, command); continue; }
+		'>>' { Parse(parser, tkGTGT, 0, command); continue; }
+		'<=' { Parse(parser, tkLTEQ, 0, command); continue; }
+		'<<' { Parse(parser, tkLTLT, 0, command); continue; }
+		'!=' { Parse(parser, tkBANGEQ, 0, command); continue; }
+		'==' { Parse(parser, tkEQEQ, 0, command); continue; }
+		'||' { Parse(parser, tkPIPEPIPE, 0, command); continue; }
+		'&&' { Parse(parser, tkAMPAMP, 0, command); continue; }
 
 
-		'(' { Parse(&parser, tkLPAREN, 0, command); continue; }
-		')' { Parse(&parser, tkRPAREN, 0, command); continue; }
-		'=' { Parse(&parser, tkEQ, 0, command); continue; }
-		'+' { Parse(&parser, tkPLUS, 0, command); continue; }
-		'-' { Parse(&parser, tkMINUS, 0, command); continue; }
-		'*' { Parse(&parser, tkSTAR, 0, command); continue; }
-		'/' { Parse(&parser, tkSLASH, 0, command); continue; }
-		'%' { Parse(&parser, tkPERCENT, 0, command); continue; }
-		'~' { Parse(&parser, tkTILDE, 0, command); continue; }
-		'!' { Parse(&parser, tkBANG, 0, command); continue; }
-		'^' { Parse(&parser, tkCARET, 0, command); continue; }
-		'&' { Parse(&parser, tkAMP, 0, command); continue; }
-		'|' { Parse(&parser, tkPIPE, 0, command); continue; }
-		'<' { Parse(&parser, tkLT, 0, command); continue; }
-		'>' { Parse(&parser, tkGT, 0, command); continue; }
+		'(' { Parse(parser, tkLPAREN, 0, command); continue; }
+		')' { Parse(parser, tkRPAREN, 0, command); continue; }
+		'=' { Parse(parser, tkEQ, 0, command); continue; }
+		'+' { Parse(parser, tkPLUS, 0, command); continue; }
+		'-' { Parse(parser, tkMINUS, 0, command); continue; }
+		'*' { Parse(parser, tkSTAR, 0, command); continue; }
+		'/' { Parse(parser, tkSLASH, 0, command); continue; }
+		'%' { Parse(parser, tkPERCENT, 0, command); continue; }
+		'~' { Parse(parser, tkTILDE, 0, command); continue; }
+		'!' { Parse(parser, tkBANG, 0, command); continue; }
+		'^' { Parse(parser, tkCARET, 0, command); continue; }
+		'&' { Parse(parser, tkAMP, 0, command); continue; }
+		'|' { Parse(parser, tkPIPE, 0, command); continue; }
+		'<' { Parse(parser, tkLT, 0, command); continue; }
+		'>' { Parse(parser, tkGT, 0, command); continue; }
 
 		[0-9]+ {
 			// integer
 			uint32_t data;
 
 			data = std::accumulate(begin, iter, 0,
-				[](char c, uint32_t value){
-					return value * 10 + c - '0';
+				[](uint32_t value, char c){
+					return (value * 10) + c - '0';
 			});
 
-			Parse(&parser, tkINTEGER, data, command);
+			Parse(parser, tkINTEGER, data, command);
 			continue;
 		}
 
@@ -169,11 +172,11 @@ bool ParseLine(const char *iter, Command *command)
 			uint32_t data;
 
 			data = std::accumulate(begin + 1, iter, 0,
-				[](char c, uint32_t value){
+				[](uint32_t value, char c){
 					return (value << 4) + tox(c);
 				}
 			);
-			Parse(&parser, tkINTEGER, data, command);
+			Parse(parser, tkINTEGER, data, command);
 			continue;
 		}
 
@@ -182,11 +185,11 @@ bool ParseLine(const char *iter, Command *command)
 			uint32_t data;
 
 			data = std::accumulate(begin + 2, iter, 0,
-				[](char c, uint32_t value){
+				[](uint32_t value, char c){
 					return (value << 4) + tox(c);
 				}
 			);
-			Parse(&parser, tkINTEGER, data, command);
+			Parse(parser, tkINTEGER, data, command);
 			continue;
 		}
 
@@ -195,12 +198,12 @@ bool ParseLine(const char *iter, Command *command)
 			uint32_t data;
 
 			data = std::accumulate(begin + 1, iter - 1, 0,
-				[](char c, uint32_t value)
+				[](uint32_t value, char c)
 				{
 					return (value << 8) + (unsigned)c;
 				}
 			);
-			Parse(&parser, tkINTEGER, data, command);
+			Parse(parser, tkINTEGER, data, command);
 			continue;
 		}
 
@@ -208,102 +211,108 @@ bool ParseLine(const char *iter, Command *command)
 		'd' [0-7] {
 			// data register
 			uint32_t data = begin[1] - '0';
-			Parse(&parser, tkDREGISTER, data, command);
+			Parse(parser, tkDREGISTER, data, command);
 			continue;
 		}
 
 		'a' [0-7] {
 			// address register
 			uint32_t data = begin[1] - '0';
-			Parse(&parser, tkAREGISTER, data, command);
+			Parse(parser, tkAREGISTER, data, command);
 			continue;
 		}
 
 		'pc' {
 			// program counter...
-			Parse(&parser, tkXREGISTER, 0, command);
+			Parse(parser, tkXREGISTER, 0, command);
 			continue;
 		}
 
 		'csr' {
 			// condition status register.
-			Parse(&parser, tkXREGISTER, 1, command);
+			Parse(parser, tkXREGISTER, 1, command);
 			continue;
 		}
 
 		'sp' {
 			// stack pointer aka a7
-			Parse(&parser, tkAREGISTER, 7, command);
+			Parse(parser, tkAREGISTER, 7, command);
 			continue;
 		}
 
 		'fp' {
 			// frame pointer aka a6
-			Parse(&parser, tkAREGISTER, 6, command);
+			Parse(parser, tkAREGISTER, 6, command);
 			continue;
 		}
 
 
 		'c' | 'continue' {
-			Parse(&parser, tkCONTINUE, 0, command);
+			Parse(parser, tkCONTINUE, 0, command);
 			continue;
 		}
 
 		'hd' | 'dump' {
-			Parse(&parser, tkDUMP, 0, command);
+			Parse(parser, tkDUMP, 0, command);
 			continue;
 		}
 
 		'h' | 'help' {
-			Parse(&parser, tkHELP, 0, command);
+			Parse(parser, tkHELP, 0, command);
 			continue;
 		}
 
 		'n' | 'next' {
-			Parse(&parser, tkNEXT, 0, command);
+			Parse(parser, tkNEXT, 0, command);
 			continue;
 		}
 
 		's' | 'step' {
-			Parse(&parser, tkNEXT, 0, command);
+			Parse(parser, tkNEXT, 0, command);
 			continue;
 		}
 
 		'b' | 'brk' | 'break' {
-			Parse(&parser, tkBREAK, 0, command);
+			Parse(parser, tkBREAK, 0, command);
 			continue;
 		}
 
 		'g' | 'go' {
-			Parse(&parser, tkCONTINUE, 0, command);
+			Parse(parser, tkCONTINUE, 0, command);
 			continue;
 		}
 
+		'p' | 'print' {
+			Parse(parser, tkPRINT, 0, command);
+			continue;
+		}
+	
 		'r' | 'run' {
-			Parse(&parser, tkCONTINUE, 0, command);
+			Parse(parser, tkCONTINUE, 0, command);
 			continue;
 		}
 
 
 		';l' | ';list' {
-			Parse(&parser, tkSEMIL, 0, command);
+			Parse(parser, tkSEMIL, 0, command);
 			continue;
 		}
 
 		';h' | ';hd' | ';hexdump' {
-			Parse(&parser, tkSEMIH, 0, command);
+			Parse(parser, tkSEMIH, 0, command);
 			continue;
 		}
 
 		[_A-Za-z][_A-Za-z0-9] + {
 			// identifier. lookup global address, tool number, etc.
-			fprintf(stderr, "illegal identifier: %*.s\n", (int)(iter - begin), begin);
+			fprintf(stderr, "illegal identifier: `%.*s`\n", (int)(iter - begin), begin);
 			return false;
 		}
 
 
 		[\x00] {
 			// eol.
+			Parse(parser, tkEOL, 0, command);
 			break;
 		}
 
@@ -316,8 +325,8 @@ bool ParseLine(const char *iter, Command *command)
 
 	}
 
-	Parse(&parser, 0, 0, command);
-	ParseFree(&parser, free);
+	Parse(parser, 0, 0, command);
+	ParseFree(parser, free);
 
 	return command->valid;
 }
\ No newline at end of file
diff --git a/debugger/parser.lemon b/debugger/parser.lemon
index 683e3b7..1282937 100644
--- a/debugger/parser.lemon
+++ b/debugger/parser.lemon
@@ -9,11 +9,23 @@
 #include <string.h>
 #include "commands.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 uint32_t cpuGetSR();
 uint32_t cpuGetPC();
 uint32_t cpuGetAReg(unsigned);
 uint32_t cpuGetDReg(unsigned);
 uint32_t debuggerReadLong(uint32_t);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#undef NDEBUG
+
 }
 
 %parse_failure {
@@ -40,40 +52,34 @@ uint32_t debuggerReadLong(uint32_t);
 %right BANG TILDE.
 
 
-stmt ::= expr(a).
+stmt ::= expr(a) EOL.
 {
-/*
-	// print the value.
-	// hex, base 10, signed 16-bit (if appropriate)
-	printf("$%08x - %u", a, a);
-
-	if (a & 0x80000000)
-		printf(" %d", (int32_t)a);
-
-	if ((a & 0xffff8000) == 0x8000)
-		printf(" %h", (int16_t)a);
-
-	printf("\n");
-*/
 	command->action = Print;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= BREAK expr(a).
+stmt ::= PRINT expr(a) EOL.
+{
+	command->action = Print;
+	command->argc = 1;
+	command->argv[0] = a;
+}
+
+stmt ::= BREAK expr(a) EOL.
 {
 	command->action = Break;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= CONTINUE.
+stmt ::= CONTINUE EOL.
 {
 	command->action = Continue;
 	command->argc = 0;
 }
 
-stmt ::= TBREAK expr(a).
+stmt ::= TBREAK expr(a) EOL.
 {
 	// negative number = remove it.
 	command->action = TBreak;
@@ -81,48 +87,41 @@ stmt ::= TBREAK expr(a).
 	command->argv[0] = a;
 }
 
-stmt ::= NEXT.
+stmt ::= NEXT EOL.
 {
 	command->action = Step;
 	command->argc = 0;
 }
 
-stmt ::= NEXT expr(a).
+stmt ::= NEXT expr(a) EOL.
 {
 	command->action = Step;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= PRINT expr(a).
-{
-	command->action = Print;
-	command->argc = 1;
-	command->argv[0] = a;
-}
-
-stmt ::= DUMP expr(a).
+stmt ::= DUMP expr(a) EOL.
 {
 	command->action = Dump;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= LIST expr(a).
+stmt ::= LIST expr(a) EOL.
 {
 	command->action = List;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= expr(a) SEMIL.
+stmt ::= expr(a) SEMIL EOL.
 {
 	command->action = List;
 	command->argc = 1;
 	command->argv[0] = a;
 }
 
-stmt ::= expr(a) SEMIH.
+stmt ::= expr(a) SEMIH EOL.
 {
 	command->action = Dump;
 	command->argc = 1;
@@ -130,7 +129,7 @@ stmt ::= expr(a) SEMIH.
 }
 
 
-stmt ::= DREGISTER(a) EQ expr(b).
+stmt ::= DREGISTER(a) EQ expr(b) EOL.
 {
 	command->action = SetDRegister;
 	command->argc = 2;
@@ -138,7 +137,7 @@ stmt ::= DREGISTER(a) EQ expr(b).
 	command->argv[1] = b;
 }
 
-stmt ::= AREGISTER(a) EQ expr(b).
+stmt ::= AREGISTER(a) EQ expr(b) EOL.
 {
 	command->action = SetARegister;
 	command->argc = 2;
@@ -146,7 +145,7 @@ stmt ::= AREGISTER(a) EQ expr(b).
 	command->argv[1] = b;
 }
 
-stmt ::= XREGISTER(a) EQ expr(b).
+stmt ::= XREGISTER(a) EQ expr(b) EOL.
 {
 	command->action = SetXRegister;
 	command->argc = 2;
@@ -154,31 +153,31 @@ stmt ::= XREGISTER(a) EQ expr(b).
 	command->argv[1] = b;
 }
 
-stmt ::= HELP .
+stmt ::= HELP EOL.
 {
 	command->action = Help;
 	command->argc = 0;
 }
 
 expr(rhs) ::= unary(a). { rhs = a; }
-expr(rhs) ::= term(a) PLUS term(b). { rhs = a + b; }
-expr(rhs) ::= term(a) MINUS term(b). { rhs = a + b; }
-expr(rhs) ::= term(a) STAR term(b). { rhs = a * b; }
-expr(rhs) ::= term(a) SLASH term(b). { rhs = a / b; }
-expr(rhs) ::= term(a) PERCENT term(b). { rhs = a % b; }
-expr(rhs) ::= term(a) LTLT term(b). { rhs = a << b; }
-expr(rhs) ::= term(a) GTGT term(b). { rhs = a >> b; }
-expr(rhs) ::= term(a) LT term(b). { rhs = a < b; }
-expr(rhs) ::= term(a) LTEQ term(b). { rhs = a <= b; }
-expr(rhs) ::= term(a) GT term(b). { rhs = a > b; }
-expr(rhs) ::= term(a) GTEQ term(b). { rhs = a >= b; }
-expr(rhs) ::= term(a) EQEQ term(b). { rhs = a == b; }
-expr(rhs) ::= term(a) BANGEQ term(b). { rhs = a != b; }
-expr(rhs) ::= term(a) AMP term(b). { rhs = a & b; }
-expr(rhs) ::= term(a) CARET term(b). { rhs = a ^ b; }
-expr(rhs) ::= term(a) PIPE term(b). { rhs = a | b; }
-expr(rhs) ::= term(a) AMPAMP term(b). { rhs = a && b; }
-expr(rhs) ::= term(a) PIPEPIPE term(b). { rhs = a || b; }
+expr(rhs) ::= expr(a) PLUS expr(b). { rhs = a + b; }
+expr(rhs) ::= expr(a) MINUS expr(b). { rhs = a - b; }
+expr(rhs) ::= expr(a) STAR expr(b). { rhs = a * b; }
+expr(rhs) ::= expr(a) SLASH expr(b). { rhs = a / b; }
+expr(rhs) ::= expr(a) PERCENT expr(b). { rhs = a % b; }
+expr(rhs) ::= expr(a) LTLT expr(b). { rhs = a << b; }
+expr(rhs) ::= expr(a) GTGT expr(b). { rhs = a >> b; }
+expr(rhs) ::= expr(a) LT expr(b). { rhs = a < b; }
+expr(rhs) ::= expr(a) LTEQ expr(b). { rhs = a <= b; }
+expr(rhs) ::= expr(a) GT expr(b). { rhs = a > b; }
+expr(rhs) ::= expr(a) GTEQ expr(b). { rhs = a >= b; }
+expr(rhs) ::= expr(a) EQEQ expr(b). { rhs = a == b; }
+expr(rhs) ::= expr(a) BANGEQ expr(b). { rhs = a != b; }
+expr(rhs) ::= expr(a) AMP expr(b). { rhs = a & b; }
+expr(rhs) ::= expr(a) CARET expr(b). { rhs = a ^ b; }
+expr(rhs) ::= expr(a) PIPE expr(b). { rhs = a | b; }
+expr(rhs) ::= expr(a) AMPAMP expr(b). { rhs = a && b; }
+expr(rhs) ::= expr(a) PIPEPIPE expr(b). { rhs = a || b; }
 
 
 unary(rhs) ::= term(a). { rhs = a; }