Implemented format() builtin call

src/namedef.h

@@ -349,6 +349,7 @@ xx(VisibleStartAngle)
 xx(VisibleStartPitch)
 xx(VisibleEndAngle)
 xx(VisibleEndPitch)
+xx(Format)
 
 // Various actor names which are used internally
 xx(MapSpot)

src/scripting/codegeneration/codegen.cpp

@@ -7115,6 +7115,14 @@ FxExpression *FxFunctionCall::Resolve(FCompileContext& ctx)
 		}
 	}
 
+	// [ZZ] string formatting function
+	if (MethodName == NAME_Format)
+	{
+		FxExpression *x = new FxFormat(ArgList, ScriptPosition);
+		delete this;
+		return x->Resolve(ctx);
+	}
+
 	int min, max, special;
 	if (MethodName == NAME_ACS_NamedExecuteWithResult || MethodName == NAME_CallACS)
 	{
@@ -8341,6 +8349,85 @@ ExpEmit FxFlopFunctionCall::Emit(VMFunctionBuilder *build)
 }
 
 
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+FxFormat::FxFormat(FArgumentList &args, const FScriptPosition &pos)
+	: FxExpression(EFX_FlopFunctionCall, pos)
+{
+	ArgList = std::move(args);
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+FxFormat::~FxFormat()
+{
+}
+
+FxExpression *FxFormat::Resolve(FCompileContext& ctx)
+{
+	CHECKRESOLVED();
+
+	for (int i = 0; i < ArgList.Size(); i++)
+	{
+		ArgList[i] = ArgList[i]->Resolve(ctx);
+		if (ArgList[i] == nullptr)
+		{
+			delete this;
+			return nullptr;
+		}
+
+		// first argument should be a string
+		if (!i && ArgList[i]->ValueType != TypeString)
+		{
+			ScriptPosition.Message(MSG_ERROR, "String was expected for format");
+			delete this;
+			return nullptr;
+		}
+
+		if (ArgList[i]->ValueType == TypeName ||
+			ArgList[i]->ValueType == TypeSound)
+		{
+			FxExpression* x = new FxStringCast(ArgList[i]);
+			x = x->Resolve(ctx);
+			if (x == nullptr)
+			{
+				delete this;
+				return nullptr;
+			}
+			ArgList[i] = x;
+		}
+	}
+
+	ValueType = TypeString;
+	return this;
+}
+
+//==========================================================================
+//
+//
+//==========================================================================
+
+ExpEmit FxFormat::Emit(VMFunctionBuilder *build)
+{
+	ExpEmit to = ExpEmit(build, REGT_STRING);
+	for (int i = 0; i < ArgList.Size(); i++)
+	{
+		EmitParameter(build, ArgList[i], ScriptPosition);
+	}
+
+	build->Emit(OP_STRFMT, to.RegNum, ArgList.Size(), 0);
+	return to;
+}
+
+
 //==========================================================================
 //
 //

src/scripting/codegeneration/codegen.h

@@ -255,6 +255,7 @@ enum EFxType
 	EFX_MemberFunctionCall,
 	EFX_ActionSpecialCall,
 	EFX_FlopFunctionCall,
+	EFX_FormatFunctionCall,
 	EFX_VMFunctionCall,
 	EFX_Sequence,
 	EFX_CompoundStatement,
@@ -1532,7 +1533,25 @@ public:
 
 //==========================================================================
 //
-//	FxFlopFunctionCall
+//	FxFormatFunctionCall
+//
+//==========================================================================
+
+class FxFormat : public FxExpression
+{
+	FArgumentList ArgList;
+
+public:
+
+	FxFormat(FArgumentList &args, const FScriptPosition &pos);
+	~FxFormat();
+	FxExpression *Resolve(FCompileContext&);
+	ExpEmit Emit(VMFunctionBuilder *build);
+};
+
+//==========================================================================
+//
+//	FxVectorBuiltin
 //
 //==========================================================================
 
@@ -1551,7 +1570,7 @@ public:
 
 //==========================================================================
 //
-//	FxFlopFunctionCall
+//	FxGetClass
 //
 //==========================================================================
 
@@ -1569,7 +1588,7 @@ public:
 
 //==========================================================================
 //
-//	FxFlopFunctionCall
+//	FxGetDefaultByType
 //
 //==========================================================================
 

src/scripting/vm/vm.h

@@ -199,6 +199,7 @@ enum EVMAbortException
 	X_ARRAY_OUT_OF_BOUNDS,
 	X_DIVISION_BY_ZERO,
 	X_BAD_SELF,
+	X_FORMAT_ERROR
 };
 
 class CVMAbortException : public CDoomError

src/scripting/vm/vmexec.h

@@ -862,6 +862,157 @@ begin:
 		}
 		NEXTOP;
 
+		OP(STRFMT) :
+		{
+			ASSERTS(a);
+			assert(B <= f->NumParam);
+			int countparam = B;
+			assert(countparam >= 1);
+			VMValue* args = reg.param + f->NumParam - B;
+			assert(args[0].Type == REGT_STRING);
+			FString fmtstring = args[0].s().GetChars();
+			
+			// note: we don't need a real printf format parser.
+			//       enough to simply find the subtitution tokens and feed them to the real printf after checking types.
+			//       https://en.wikipedia.org/wiki/Printf_format_string#Format_placeholder_specification
+			FString output;
+			bool in_fmt = false;
+			FString fmt_current;
+			int argnum = 1;
+			int argauto = 1;
+			// % = starts
+			//  [0-9], -, +, \s, 0, #, . continue
+			//  %, s, d, i, u, fF, eE, gG, xX, o, c, p, aA terminate
+			// various type flags are not supported. not like stuff like 'hh' modifier is to be used in the VM.
+			// the only combination that is parsed locally is %n$...
+			bool haveargnums = false;
+			for (int i = 0; i < fmtstring.Len(); i++)
+			{
+				char c = fmtstring[i];
+				if (in_fmt)
+				{
+					if ((c >= '0' && c <= '9') ||
+						c == '-' || c == '+' || (c == ' ' && fmt_current[fmt_current.Len() - 1] != ' ') || c == '#' || c == '.')
+					{
+						fmt_current += c;
+					}
+					else if (c == '$') // %number$format
+					{
+						if (!haveargnums && argauto > 1)
+							ThrowAbortException(X_FORMAT_ERROR, "Cannot mix explicit and implicit arguments.");
+						FString argnumstr = fmt_current.Mid(1);
+						if (!argnumstr.IsInt()) ThrowAbortException(X_FORMAT_ERROR, "Expected a numeric value for argument number, got '%s'.", argnumstr.GetChars());
+						argnum = argnumstr.ToLong();
+						if (argnum < 1 || argnum >= countparam) ThrowAbortException(X_FORMAT_ERROR, "Not enough arguments for format (tried to access argument %d, %d total).", argnum, countparam);
+						fmt_current = "%";
+						haveargnums = true;
+					}
+					else
+					{
+						fmt_current += c;
+
+						switch (c)
+						{
+							// string and char formats
+						case 's':
+						{
+							if (argnum < 0 && haveargnums)
+								ThrowAbortException(X_FORMAT_ERROR, "Cannot mix explicit and implicit arguments.");
+							in_fmt = false;
+							// fail if something was found, but it's not a string
+							if (argnum >= countparam) ThrowAbortException(X_FORMAT_ERROR, "Not enough arguments for format.");
+							if (args[argnum].Type != REGT_STRING) ThrowAbortException(X_FORMAT_ERROR, "Expected a string for format %s.", fmt_current.GetChars());
+							// append
+							output.AppendFormat(fmt_current.GetChars(), args[argnum].s().GetChars());
+							if (!haveargnums) argnum = ++argauto;
+							else argnum = -1;
+							break;
+						}
+
+						// int formats
+						case 'd':
+						case 'i':
+						case 'u':
+						case 'x':
+						case 'X':
+						case 'o':
+						{
+							if (argnum < 0 && haveargnums)
+								ThrowAbortException(X_FORMAT_ERROR, "Cannot mix explicit and implicit arguments.");
+							in_fmt = false;
+							// fail if something was found, but it's not an int
+							if (argnum >= countparam) ThrowAbortException(X_FORMAT_ERROR, "Not enough arguments for format.");
+							if (args[argnum].Type != REGT_INT &&
+								args[argnum].Type != REGT_FLOAT) ThrowAbortException(X_FORMAT_ERROR, "Expected a numeric value for format %s.", fmt_current.GetChars());
+							// append
+							output.AppendFormat(fmt_current.GetChars(), args[argnum].ToInt());
+							if (!haveargnums) argnum = ++argauto;
+							else argnum = -1;
+							break;
+						}
+
+						// double formats
+						case 'f':
+						case 'F':
+						case 'e':
+						case 'E':
+						case 'g':
+						case 'G':
+						case 'a':
+						case 'A':
+						{
+							if (argnum < 0 && haveargnums)
+								ThrowAbortException(X_FORMAT_ERROR, "Cannot mix explicit and implicit arguments.");
+							in_fmt = false;
+							// fail if something was found, but it's not a float
+							if (argnum >= countparam) ThrowAbortException(X_FORMAT_ERROR, "Not enough arguments for format.");
+							if (args[argnum].Type != REGT_INT &&
+								args[argnum].Type != REGT_FLOAT) ThrowAbortException(X_FORMAT_ERROR, "Expected a numeric value for format %s.", fmt_current.GetChars());
+							// append
+							output.AppendFormat(fmt_current.GetChars(), args[argnum].ToDouble());
+							if (!haveargnums) argnum = ++argauto;
+							else argnum = -1;
+							break;
+						}
+
+						default:
+							// invalid character
+							output += fmt_current;
+							in_fmt = false;
+							break;
+						}
+					}
+				}
+				else
+				{
+					if (c == '%')
+					{
+						if (i + 1 < fmtstring.Len() && fmtstring[i + 1] == '%')
+						{
+							output += '%';
+							i++;
+						}
+						else
+						{
+							in_fmt = true;
+							fmt_current = "%";
+						}
+					}
+					else
+					{
+						output += c;
+					}
+				}
+			}
+
+			// finalize parameters
+			for (b = B; b != 0; --b)
+				reg.param[--f->NumParam].~VMValue();
+
+			reg.s[a] = output;
+		}
+		NEXTOP;
+
 	OP(SLL_RR):
 		ASSERTD(a); ASSERTD(B); ASSERTD(C);
 		reg.d[a] = reg.d[B] << reg.d[C];

src/scripting/vm/vmframe.cpp

@@ -549,6 +549,10 @@ CVMAbortException::CVMAbortException(EVMAbortException reason, const char *morei
 		AppendMessage("invalid self pointer.");
 		break;
 
+	case X_FORMAT_ERROR:
+		AppendMessage("string format failed.");
+		break;
+
 	default:
 	{
 		size_t len = strlen(m_Message);

src/scripting/vm/vmops.h

@@ -120,6 +120,7 @@ xx(BOUND_R,	bound,	RIRI,		NOP,	0, 0),		// if rA >= rB, throw exception
 xx(CONCAT,		concat,	RSRSRS,		NOP,	0, 0),		// sA = sB..sC
 xx(LENS,		lens,	RIRS,		NOP,	0, 0),			// dA = sB.Length
 xx(CMPS,		cmps,	I8RXRX,		NOP,	0, 0),		// if ((skB op skC) != (A & 1)) then pc++
+xx(STRFMT,      strfmt, RIRIRI,     NOP,  0, 0),
 
 // Integer math.
 xx(SLL_RR,		sll,	RIRIRI,		NOP,	0, 0),		// dA = dkB << diC