Added some more comments.

Added the beginnings of a debugger. It's not useful yet.

Makefile

@@ -4,7 +4,7 @@ LIBS=-lm -lreadline
 
 TARGET = picoc
 SRCS = picoc.c table.c lex.c parse.c expression.c heap.c type.c \
- variable.c clibrary.c platform.c include.c \
+ variable.c clibrary.c platform.c include.c debug.c \
  platform/platform_unix.c platform/library_unix.c \
  cstdlib/stdio.c cstdlib/math.c cstdlib/string.c cstdlib/stdlib.c \
  cstdlib/time.c cstdlib/errno.c cstdlib/ctype.c cstdlib/stdbool.c \
@@ -24,7 +24,7 @@ clean:
 
 count:
  @echo "Core:"
- @cat picoc.h interpreter.h picoc.c table.c lex.c parse.c expression.c platform.c heap.c type.c variable.c include.c | grep -v '^[ ]*/\*' | grep -v '^[ ]*$$' | wc
+ @cat picoc.h interpreter.h picoc.c table.c lex.c parse.c expression.c platform.c heap.c type.c variable.c include.c debug.c | grep -v '^[ ]*/\*' | grep -v '^[ ]*$$' | wc
  @echo ""
  @echo "Everything:"
  @cat $(SRCS) *.h */*.h | wc
@@ -42,6 +42,7 @@ variable.o: variable.c interpreter.h platform.h
 clibrary.o: clibrary.c picoc.h interpreter.h platform.h
 platform.o: platform.c picoc.h interpreter.h platform.h
 include.o: include.c picoc.h interpreter.h platform.h
+debug.o: debug.c interpreter.h platform.h
 platform/platform_unix.o: platform/platform_unix.c picoc.h interpreter.h platform.h
 platform/library_unix.o: platform/library_unix.c interpreter.h platform.h
 cstdlib/stdio.o: cstdlib/stdio.c interpreter.h platform.h

clibrary.c

@@ -1,3 +1,6 @@
+/* picoc mini standard C library - provides an optional tiny C standard library 
+ * if BUILTIN_MINI_STDLIB is defined */ 
+
 #include "picoc.h"
 #include "interpreter.h"
 
@@ -35,13 +38,13 @@ void LibraryAdd(struct Table *GlobalTable, const char *LibraryName, struct Libra
  struct ValueType *ReturnType;
  struct Value *NewValue;
  void *Tokens;
- const char *IntrinsicName = TableStrRegister("c library");
+ char *IntrinsicName = TableStrRegister("c library");
 
  /* read all the library definitions */
  for (Count = 0; FuncList[Count].Prototype != NULL; Count++)
  {
  Tokens = LexAnalyse(IntrinsicName, FuncList[Count].Prototype, strlen((char *)FuncList[Count].Prototype), NULL);
- LexInitParser(&Parser, FuncList[Count].Prototype, Tokens, IntrinsicName, TRUE);
+ LexInitParser(&Parser, FuncList[Count].Prototype, Tokens, IntrinsicName, TRUE, FALSE);
  TypeParse(&Parser, &ReturnType, &Identifier, NULL);
  NewValue = ParseFunctionDefinition(&Parser, ReturnType, Identifier);
  NewValue->Val->FuncDef.Intrinsic = FuncList[Count].Func;

debug.c

@@ -0,0 +1,127 @@
+/* picoc interactive debugger */
+
+#ifndef NO_DEBUGGER
+
+#include "interpreter.h"
+
+#define BREAKPOINT_TABLE_SIZE 21
+#define BREAKPOINT_HASH(p) ( ((unsigned long)(p)->FileName) ^ (((p)->Line << 16) | ((p)->CharacterPos << 16)) )
+
+struct Table BreakpointTable;
+struct TableEntry *BreakpointHashTable[BREAKPOINT_TABLE_SIZE];
+int BreakpointCount = 0;
+int DebugManualBreak = FALSE;
+
+/* initialise the debugger by clearing the breakpoint table */
+void DebugInit()
+{
+ TableInitTable(&BreakpointTable, &BreakpointHashTable[0], BREAKPOINT_TABLE_SIZE, TRUE);
+ BreakpointCount = 0;
+}
+
+/* free the contents of the breakpoint table */
+void DebugCleanup()
+{
+ struct TableEntry *Entry;
+ struct TableEntry *NextEntry;
+ int Count;
+
+ for (Count = 0; Count < BreakpointTable.Size; Count++)
+ {
+ for (Entry = BreakpointHashTable[Count]; Entry != NULL; Entry = NextEntry)
+ {
+ NextEntry = Entry->Next;
+ HeapFreeMem(Entry);
+ }
+ }
+}
+
+/* search the table for a breakpoint */
+static struct TableEntry *DebugTableSearchBreakpoint(struct ParseState *Parser, int *AddAt)
+{
+ struct TableEntry *Entry;
+ int HashValue = BREAKPOINT_HASH(Parser) % BreakpointTable.Size;
+
+ for (Entry = BreakpointHashTable[HashValue]; Entry != NULL; Entry = Entry->Next)
+ {
+ if (Entry->p.b.FileName == Parser->FileName && Entry->p.b.Line == Parser->Line && Entry->p.b.CharacterPos == Parser->CharacterPos)
+ return Entry; /* found */
+ }
+
+ *AddAt = HashValue; /* didn't find it in the chain */
+ return NULL;
+}
+
+/* set a breakpoint in the table */
+void DebugSetBreakpoint(struct ParseState *Parser)
+{
+ int AddAt;
+ struct TableEntry *FoundEntry = DebugTableSearchBreakpoint(Parser, &AddAt);
+
+ if (FoundEntry == NULL)
+ { 
+ /* add it to the table */
+ struct TableEntry *NewEntry = HeapAllocMem(sizeof(struct TableEntry));
+ if (NewEntry == NULL)
+ ProgramFail(NULL, "out of memory");
+
+ NewEntry->p.b.FileName = Parser->FileName;
+ NewEntry->p.b.Line = Parser->Line;
+ NewEntry->p.b.CharacterPos = Parser->CharacterPos;
+ NewEntry->Next = BreakpointHashTable[AddAt];
+ BreakpointHashTable[AddAt] = NewEntry;
+ BreakpointCount++;
+ }
+}
+
+/* delete a breakpoint from the hash table */
+int DebugClearBreakpoint(struct ParseState *Parser)
+{
+ struct TableEntry **EntryPtr;
+ int HashValue = BREAKPOINT_HASH(Parser) % BreakpointTable.Size;
+
+ for (EntryPtr = &BreakpointHashTable[HashValue]; *EntryPtr != NULL; EntryPtr = &(*EntryPtr)->Next)
+ {
+ struct TableEntry *DeleteEntry = *EntryPtr;
+ if (DeleteEntry->p.b.FileName == Parser->FileName && DeleteEntry->p.b.Line == Parser->Line && DeleteEntry->p.b.CharacterPos == Parser->CharacterPos)
+ {
+ *EntryPtr = DeleteEntry->Next;
+ HeapFreeMem(DeleteEntry);
+ BreakpointCount--;
+
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+/* before we run a statement, check if there's anything we have to do with the debugger here */
+void DebugCheckStatement(struct ParseState *Parser)
+{
+ int DoBreak = FALSE;
+ int AddAt;
+
+ /* has the user manually pressed break? */
+ if (DebugManualBreak)
+ {
+ DoBreak = TRUE;
+ DebugManualBreak = FALSE;
+ }
+
+ /* is this a breakpoint location? */
+ if (BreakpointCount != 0 && DebugTableSearchBreakpoint(Parser, &AddAt) != NULL)
+ DoBreak = TRUE;
+
+ /* handle a break */
+ if (DoBreak)
+ {
+ PlatformPrintf("Handling a break\n");
+ PicocParseInteractiveNoStartPrompt(FALSE);
+ }
+}
+
+void DebugStep()
+{
+}
+#endif /* !NO_DEBUGGER */

expression.c

@@ -1,6 +1,8 @@
+/* picoc expression evaluator - a stack-based expression evaluation system
+ * which handles operator precedence */
+
 #include "interpreter.h"
 
-
 /* whether evaluation is left to right for a given precedence level */
 #define IS_LEFT_TO_RIGHT(p) ((p) != 2 && (p) != 14)
 #define BRACKET_PRECEDENCE 20

heap.c

@@ -1,3 +1,7 @@
+/* picoc heap memory allocation. This is a complete (but small) memory
+ * allocator for embedded systems which have no memory allocator. Alternatively
+ * you can define USE_MALLOC_HEAP to use your system's own malloc() allocator */
+
 /* stack grows up from the bottom and heap grows down from the top of heap space */
 #include "interpreter.h"
 

include.c

@@ -1,3 +1,6 @@
+/* picoc include system - can emulate system includes from built-in libraries
+ * or it can include and parse files if the system has files */
+
 #include "picoc.h"
 #include "interpreter.h"
 
@@ -92,7 +95,7 @@ void IncludeFile(char *FileName)
 
  /* parse the setup C source code - may define types etc. */
  if (LInclude->SetupCSource != NULL)
- PicocParse(FileName, LInclude->SetupCSource, strlen(LInclude->SetupCSource), TRUE, TRUE, FALSE);
+ PicocParse(FileName, LInclude->SetupCSource, strlen(LInclude->SetupCSource), TRUE, TRUE, FALSE, FALSE);
 
  /* set up the library functions */
  if (LInclude->FuncList != NULL)

interpreter.h

@@ -1,3 +1,7 @@
+/* picoc main header file - this has all the main data structures and 
+ * function prototypes. If you're just calling picoc you should look at the
+ * external interface instead, in picoc.h */
+
 #ifndef INTERPRETER_H
 #define INTERPRETER_H
 
@@ -104,16 +108,17 @@ enum RunMode
 /* parser state - has all this detail so we can parse nested files */
 struct ParseState
 {
- const unsigned char *Pos;
- const char *FileName;
- short int Line;
- short int CharacterPos;
+ const unsigned char *Pos; /* the character position in the source text */
+ char *FileName; /* what file we're executing (registered string) */
+ short int Line; /* line number we're executing */
+ short int CharacterPos; /* character/column in the line we're executing */
  enum RunMode Mode; /* whether to skip or run code */
  int SearchLabel; /* what case label we're searching for */
  const char *SearchGotoLabel;/* what goto label we're searching for */
- short int HashIfLevel;
- short int HashIfEvaluateToLevel;
- const char *SourceText;
+ const char *SourceText; /* the entire source text */
+ short int HashIfLevel; /* how many "if"s we're nested down */
+ short int HashIfEvaluateToLevel; /* if we're not evaluating an if branch, what the last evaluated level was */
+ char DebugMode; /* debugging mode */
 };
 
 /* values */
@@ -225,6 +230,14 @@ struct TableEntry
  } v; /* used for tables of values */
 
  char Key[1]; /* dummy size - used for the shared string table */
+
+ struct BreakpointEntry /* defines a breakpoint */
+ {
+ const char *FileName;
+ short int Line;
+ short int CharacterPos;
+ } b;
+
  } p;
 };
 
@@ -340,7 +353,7 @@ void TableStrFree();
 void LexInit();
 void LexCleanup();
 void *LexAnalyse(const char *FileName, const char *Source, int SourceLen, int *TokenLen);
-void LexInitParser(struct ParseState *Parser, const char *SourceText, void *TokenSource, const char *FileName, int RunIt);
+void LexInitParser(struct ParseState *Parser, const char *SourceText, void *TokenSource, char *FileName, int RunIt, int SetDebugMode);
 enum LexToken LexGetToken(struct ParseState *Parser, struct Value **Value, int IncPos);
 enum LexToken LexRawPeekToken(struct ParseState *Parser);
 void LexToEndOfLine(struct ParseState *Parser);
@@ -353,6 +366,7 @@ void LexInteractiveStatementPrompt();
 /* the following are defined in picoc.h:
  * void PicocParse(const char *FileName, const char *Source, int SourceLen, int RunIt, int CleanupNow, int CleanupSource);
  * void PicocParseInteractive(); */
+void PicocParseInteractiveNoStartPrompt(int EnableDebugger);
 enum ParseResult ParseStatement(struct ParseState *Parser, int CheckTrailingSemicolon);
 struct Value *ParseFunctionDefinition(struct ParseState *Parser, struct ValueType *ReturnType, char *Identifier);
 void ParseCleanup();
@@ -440,6 +454,7 @@ void LibPrintf(struct ParseState *Parser, struct Value *ReturnValue, struct Valu
 void ProgramFail(struct ParseState *Parser, const char *Message, ...);
 void AssignFail(struct ParseState *Parser, const char *Format, struct ValueType *Type1, struct ValueType *Type2, int Num1, int Num2, const char *FuncName, int ParamNo);
 void LexFail(struct LexState *Lexer, const char *Message, ...);
+void PlatformInit();
 void PlatformCleanup();
 char *PlatformGetLine(char *Buf, int MaxLen, const char *Prompt);
 int PlatformGetCharacter();
@@ -458,6 +473,13 @@ void IncludeRegister(const char *IncludeName, void (*SetupFunction)(void), struc
 void IncludeFile(char *Filename);
 /* the following is defined in picoc.h:
  * void PicocIncludeAllSystemHeaders(); */
+
+/* debug.c */
+extern int DebugManualBreak;
+void DebugInit();
+void DebugCleanup();
+void DebugCheckStatement(struct ParseState *Parser);
+
 
 /* stdio.c */
 extern const char StdioDefs[];

lex.c

@@ -1,3 +1,5 @@
+/* picoc lexer - converts source text into a tokenised form */ 
+
 #include "interpreter.h"
 
 #ifdef NO_CTYPE
@@ -583,7 +585,7 @@ void *LexAnalyse(const char *FileName, const char *Source, int SourceLen, int *T
 }
 
 /* prepare to parse a pre-tokenised buffer */
-void LexInitParser(struct ParseState *Parser, const char *SourceText, void *TokenSource, const char *FileName, int RunIt)
+void LexInitParser(struct ParseState *Parser, const char *SourceText, void *TokenSource, char *FileName, int RunIt, int EnableDebugger)
 {
  Parser->Pos = TokenSource;
  Parser->Line = 1;
@@ -594,6 +596,7 @@ void LexInitParser(struct ParseState *Parser, const char *SourceText, void *Toke
  Parser->HashIfEvaluateToLevel = 0;
  Parser->CharacterPos = 0;
  Parser->SourceText = SourceText;
+ Parser->DebugMode = EnableDebugger;
 }
 
 /* get the next token, without pre-processing */

parse.c

@@ -1,3 +1,5 @@
+/* picoc parser - parses source and executes statements */
+
 #include "picoc.h"
 #include "interpreter.h"
 
@@ -484,6 +486,11 @@ enum ParseResult ParseStatement(struct ParseState *Parser, int CheckTrailingSemi
  struct ParseState PreState;
  enum LexToken Token;
 
+ /* if we're debugging, check for a breakpoint */
+ if (Parser->DebugMode && Parser->Mode == RunModeRun)
+ DebugCheckStatement(Parser);
+
+ /* take note of where we are and then grab a token to see what statement we have */ 
  ParserCopy(&PreState, Parser);
  Token = LexGetToken(Parser, &LexerValue, TRUE);
 
@@ -806,13 +813,14 @@ enum ParseResult ParseStatement(struct ParseState *Parser, int CheckTrailingSemi
 }
 
 /* quick scan a source file for definitions */
-void PicocParse(const char *FileName, const char *Source, int SourceLen, int RunIt, int CleanupNow, int CleanupSource)
+void PicocParse(const char *FileName, const char *Source, int SourceLen, int RunIt, int CleanupNow, int CleanupSource, int EnableDebugger)
 {
  struct ParseState Parser;
  enum ParseResult Ok;
  struct CleanupTokenNode *NewCleanupNode;
+ char *RegFileName = TableStrRegister(FileName);
 
- void *Tokens = LexAnalyse(FileName, Source, SourceLen, NULL);
+ void *Tokens = LexAnalyse(RegFileName, Source, SourceLen, NULL);
 
  /* allocate a cleanup node so we can clean up the tokens later */
  if (!CleanupNow)
@@ -832,7 +840,7 @@ void PicocParse(const char *FileName, const char *Source, int SourceLen, int Run
  }
 
  /* do the parsing */
- LexInitParser(&Parser, Source, Tokens, FileName, RunIt);
+ LexInitParser(&Parser, Source, Tokens, RegFileName, RunIt, EnableDebugger);
 
  do {
  Ok = ParseStatement(&Parser, TRUE);
@@ -847,13 +855,12 @@ void PicocParse(const char *FileName, const char *Source, int SourceLen, int Run
 }
 
 /* parse interactively */
-void PicocParseInteractive()
+void PicocParseInteractiveNoStartPrompt(int EnableDebugger)
 {
  struct ParseState Parser;
  enum ParseResult Ok;
 
- PlatformPrintf(INTERACTIVE_PROMPT_START);
- LexInitParser(&Parser, NULL, NULL, StrEmpty, TRUE);
+ LexInitParser(&Parser, NULL, NULL, StrEmpty, TRUE, EnableDebugger);
  PicocPlatformSetExitPoint();
  LexInteractiveClear(&Parser);
 
@@ -870,3 +877,10 @@ void PicocParseInteractive()
 
  PlatformPrintf("\n");
 }
+
+/* parse interactively, showing a startup message */
+void PicocParseInteractive()
+{
+ PlatformPrintf(INTERACTIVE_PROMPT_START);
+ PicocParseInteractiveNoStartPrompt(TRUE);
+}