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gzdoom/src/thingdef/thingdef_states.cpp
Randy Heit b2ccd0bd28 Use action function return value to make state jumps happen 
- The A_Jump family of action functions now return the state to jump
  to (NULL if no jump is to be taken) instead of jumping directly.
  It is the caller's responsibility to handle the jump. This will
  make it possible to use their results in if statements and
  do something other than jump.
- DECORATE return statements can now return the result of a function
  (but not any random expression--it must be a function call). To
  make a jump happen from inside a multi-action block, you must
  return the value of an A_Jump function. e.g.:
    { return A_Jump(128, "SomeState"); }
- The VMFunction class now contains its prototype instead of storing
  it at a higher level in PFunction. This is so that
  FState::CallAction can easily tell if a function returns a state.
- Removed the FxTailable class because with explicit return
  statements, it's not useful anymore.
2016-02-18 20:39:40 -06:00

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/*
** thingdef_states.cpp
**
** Actor definitions - the state parser
**
**---------------------------------------------------------------------------
** Copyright 2002-2007 Christoph Oelckers
** Copyright 2004-2007 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
** 4. When not used as part of ZDoom or a ZDoom derivative, this code will be
** covered by the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or (at
** your option) any later version.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
#include "actor.h"
#include "info.h"
#include "sc_man.h"
#include "tarray.h"
#include "templates.h"
#include "cmdlib.h"
#include "p_lnspec.h"
#include "a_action.h"
#include "p_local.h"
#include "v_palette.h"
#include "doomerrors.h"
#include "thingdef.h"
#include "a_sharedglobal.h"
#include "s_sound.h"
#include "i_system.h"
#include "colormatcher.h"
#include "thingdef_exp.h"
#include "version.h"
#include "templates.h"
TDeletingArray<FStateTempCall *> StateTempCalls;
//==========================================================================
//***
// DoActionSpecials
// handles action specials as code pointers
//
//==========================================================================
FxVMFunctionCall *DoActionSpecials(FScanner &sc, FState & state, Baggage &bag)
{
int i;
int min_args, max_args;
FString specname = sc.String;
int special = P_FindLineSpecial(sc.String, &min_args, &max_args);
if (special > 0 && min_args >= 0)
{
FArgumentList *args = new FArgumentList;
args->Push(new FxParameter(new FxConstant(special, sc)));
i = 0;
// Make this consistent with all other parameter parsing
if (sc.CheckToken('('))
{
while (i < 5)
{
args->Push(new FxParameter(new FxIntCast(ParseExpression(sc, bag.Info))));
i++;
if (!sc.CheckToken (',')) break;
}
sc.MustGetToken (')');
}
if (i < min_args)
{
sc.ScriptError ("Too few arguments to %s", specname.GetChars());
}
if (i > max_args)
{
sc.ScriptError ("Too many arguments to %s", specname.GetChars());
}
return new FxVMFunctionCall(FindGlobalActionFunction("A_CallSpecial"), args, sc);
}
return NULL;
}
//==========================================================================
//***
// Reads a state label that may contain '.'s.
// processes a state block
//
//==========================================================================
static FString ParseStateString(FScanner &sc)
{
FString statestring;
sc.MustGetString();
statestring = sc.String;
if (sc.CheckString("::"))
{
sc.MustGetString ();
statestring << "::" << sc.String;
}
while (sc.CheckString ("."))
{
sc.MustGetString ();
statestring << "." << sc.String;
}
return statestring;
}
//==========================================================================
//***
// ParseStates
// parses a state block
//
//==========================================================================
void ParseStates(FScanner &sc, PClassActor * actor, AActor * defaults, Baggage &bag)
{
FString statestring;
FState state;
char lastsprite[5] = "";
FStateTempCall *tcall = NULL;
FArgumentList *args = NULL;
sc.MustGetStringName ("{");
sc.SetEscape(false); // disable escape sequences in the state parser
while (!sc.CheckString ("}") && !sc.End)
{
memset(&state,0,sizeof(state));
statestring = ParseStateString(sc);
if (!statestring.CompareNoCase("GOTO"))
{
do_goto:
statestring = ParseStateString(sc);
if (sc.CheckString ("+"))
{
sc.MustGetNumber ();
statestring += '+';
statestring += sc.String;
}
if (!bag.statedef.SetGotoLabel(statestring))
{
sc.ScriptError("GOTO before first state");
}
}
else if (!statestring.CompareNoCase("STOP"))
{
do_stop:
if (!bag.statedef.SetStop())
{
sc.ScriptError("STOP before first state");
continue;
}
}
else if (!statestring.CompareNoCase("WAIT") || !statestring.CompareNoCase("FAIL"))
{
if (!bag.statedef.SetWait())
{
sc.ScriptError("%s before first state", sc.String);
continue;
}
}
else if (!statestring.CompareNoCase("LOOP"))
{
if (!bag.statedef.SetLoop())
{
sc.ScriptError("LOOP before first state");
continue;
}
}
else
{
sc.MustGetString();
if (sc.Compare (":"))
{
do
{
bag.statedef.AddStateLabel(statestring);
statestring = ParseStateString(sc);
if (!statestring.CompareNoCase("GOTO"))
{
goto do_goto;
}
else if (!statestring.CompareNoCase("STOP"))
{
goto do_stop;
}
sc.MustGetString ();
} while (sc.Compare (":"));
// continue;
}
sc.UnGet ();
if (statestring.Len() != 4)
{
sc.ScriptError ("Sprite names must be exactly 4 characters\n");
}
state.sprite = GetSpriteIndex(statestring);
state.Misc1 = state.Misc2 = 0;
sc.MustGetString();
statestring = sc.String;
if (tcall == NULL)
{
tcall = new FStateTempCall;
}
if (sc.CheckString("RANDOM"))
{
int min, max;
sc.MustGetStringName("(");
sc.MustGetNumber();
min = clamp<int>(sc.Number, -1, SHRT_MAX);
sc.MustGetStringName(",");
sc.MustGetNumber();
max = clamp<int>(sc.Number, -1, SHRT_MAX);
sc.MustGetStringName(")");
if (min > max)
{
swapvalues(min, max);
}
state.Tics = min;
state.TicRange = max - min;
}
else
{
sc.MustGetNumber();
state.Tics = clamp<int>(sc.Number, -1, SHRT_MAX);
state.TicRange = 0;
}
while (sc.GetString() && (!sc.Crossed || sc.Compare("{")))
{
if (sc.Compare("BRIGHT"))
{
state.Fullbright = true;
continue;
}
if (sc.Compare("FAST"))
{
state.Fast = true;
continue;
}
if (sc.Compare("SLOW"))
{
state.Slow = true;
continue;
}
if (sc.Compare("NODELAY"))
{
if (bag.statedef.GetStateLabelIndex(NAME_Spawn) == bag.statedef.GetStateCount())
{
state.NoDelay = true;
}
else
{
sc.ScriptMessage("NODELAY may only be used immediately after Spawn:");
}
continue;
}
if (sc.Compare("OFFSET"))
{
// specify a weapon offset
sc.MustGetStringName("(");
sc.MustGetNumber();
state.Misc1 = sc.Number;
sc.MustGetStringName (",");
sc.MustGetNumber();
state.Misc2 = sc.Number;
sc.MustGetStringName(")");
continue;
}
if (sc.Compare("LIGHT"))
{
sc.MustGetStringName("(");
do
{
sc.MustGetString();
#ifdef DYNLIGHT
AddStateLight(&state, sc.String);
#endif
}
while (sc.CheckString(","));
sc.MustGetStringName(")");
continue;
}
if (sc.Compare("CANRAISE"))
{
state.CanRaise = true;
continue;
}
bool hasfinalret;
tcall->Code = ParseActions(sc, state, statestring, bag, tcall->Proto, hasfinalret);
if (!hasfinalret)
{
AddImplicitReturn(static_cast<FxSequence*>(tcall->Code), tcall->Proto, sc);
}
goto endofstate;
}
sc.UnGet();
endofstate:
int count = bag.statedef.AddStates(&state, statestring);
if (count < 0)
{
sc.ScriptError ("Invalid frame character string '%s'", statestring.GetChars());
count = -count;
}
if (tcall->Code != NULL)
{
tcall->ActorClass = actor;
tcall->FirstState = bag.statedef.GetStateCount() - count;
tcall->NumStates = count;
StateTempCalls.Push(tcall);
tcall = NULL;
}
}
}
if (tcall != NULL)
{
delete tcall;
}
if (args != NULL)
{
delete args;
}
sc.SetEscape(true); // re-enable escape sequences
}
//==========================================================================
//
// AddImplicitReturn
//
// Adds an implied return; statement to the end of a code sequence.
//
//==========================================================================
void AddImplicitReturn(FxSequence *code, const PPrototype *proto, FScanner &sc)
{
if (proto == NULL || proto->ReturnTypes.Size() == 0)
{ // Returns nothing. Good. We can safely add an implied return.
code->Add(new FxReturnStatement(NULL, sc));
}
else
{ // Something was returned earlier in the sequence. Make it an error
// instead of adding an implicit one.
sc.ScriptError("Action list must end with a return statement");
}
}
//==========================================================================
//
// ReturnCheck
//
// If proto1 is NULL, returns proto2. If proto2 is NULL, returns proto1.
// If neither is null, checks if both prototypes define the same return
// types. If not, an error is flagged.
//
//==========================================================================
static PPrototype *ReturnCheck(PPrototype *proto1, PPrototype *proto2, FScanner &sc)
{
if (proto1 == NULL)
{
return proto2;
}
if (proto2 == NULL)
{
return proto1;
}
// A prototype that defines fewer return types can be compatible with
// one that defines more if the shorter one matches the initial types
// for the longer one.
if (proto2->ReturnTypes.Size() < proto1->ReturnTypes.Size())
{ // Make proto1 the shorter one to avoid code duplication below.
swapvalues(proto1, proto2);
}
// If one prototype returns nothing, they both must.
if (proto1->ReturnTypes.Size() == 0)
{
if (proto2->ReturnTypes.Size() == 0)
{
return proto1;
}
proto1 = NULL;
}
else
{
for (unsigned i = 0; i < proto1->ReturnTypes.Size(); ++i)
{
if (proto1->ReturnTypes[i] != proto2->ReturnTypes[i])
{ // Incompatible
proto1 = NULL;
break;
}
}
}
if (proto1 == NULL)
{
sc.ScriptError("Return types are incompatible");
}
return proto1;
}
//==========================================================================
//
// ParseActions
//
// If this action block contains any return statements, the prototype for
// one of them will be returned. This is used for deducing the return type
// of anonymous functions. All called functions passed to return must have
// matching return types.
//
//==========================================================================
FxExpression *ParseActions(FScanner &sc, FState state, FString statestring, Baggage &bag,
PPrototype *&retproto, bool &endswithret)
{
// If it's not a '{', then it should be a single action.
// Otherwise, it's a sequence of actions.
if (!sc.Compare("{"))
{
FxVMFunctionCall *call = ParseAction(sc, state, statestring, bag);
retproto = call->GetVMFunction()->Proto;
endswithret = true;
return new FxReturnStatement(call, sc);
}
const FScriptPosition pos(sc);
FxSequence *seq = NULL;
PPrototype *proto = NULL;
bool lastwasret = false;
sc.MustGetString();
while (!sc.Compare("}"))
{
FxExpression *add;
lastwasret = false;
if (sc.Compare("if"))
{ // Hangle an if statement
FxExpression *cond;
FxExpression *true_part, *false_part = NULL;
PPrototype *true_proto, *false_proto = NULL;
bool true_ret, false_ret = false;
sc.MustGetStringName("(");
cond = ParseExpression(sc, bag.Info);
sc.MustGetStringName(")");
sc.MustGetStringName("{"); // braces are mandatory
true_part = ParseActions(sc, state, statestring, bag, true_proto, true_ret);
sc.MustGetString();
if (sc.Compare("else"))
{
sc.MustGetStringName("{"); // braces are still mandatory
false_part = ParseActions(sc, state, statestring, bag, false_proto, false_ret);
sc.MustGetString();
}
add = new FxIfStatement(cond, true_part, false_part, sc);
proto = ReturnCheck(proto, true_proto, sc);
proto = ReturnCheck(proto, false_proto, sc);
// If one side does not end with a return, we don't consider the if statement
// to end with a return.
if (true_ret && (false_proto == NULL || false_ret))
{
lastwasret = true;
}
}
else if (sc.Compare("return"))
{ // Handle a return statement
lastwasret = true;
FxVMFunctionCall *retexp = NULL;
PPrototype *retproto;
sc.MustGetString();
if (!sc.Compare(";"))
{
retexp = ParseAction(sc, state, statestring, bag);
sc.MustGetStringName(";");
retproto = retexp->GetVMFunction()->Proto;
}
else
{ // Returning nothing; we still need a prototype for that.
TArray<PType *> notypes(0);
retproto = NewPrototype(notypes, notypes);
}
proto = ReturnCheck(proto, retproto, sc);
sc.MustGetString();
add = new FxReturnStatement(retexp, sc);
}
else
{ // Handle a regular action function call
add = ParseAction(sc, state, statestring, bag);
sc.MustGetStringName(";");
sc.MustGetString();
}
// Only return a sequence if it has actual content.
if (add != NULL)
{
if (seq == NULL)
{
seq = new FxSequence(pos);
}
seq->Add(add);
}
}
endswithret = lastwasret;
retproto = proto;
return seq;
}
//==========================================================================
//
// ParseAction
//
//==========================================================================
FxVMFunctionCall *ParseAction(FScanner &sc, FState state, FString statestring, Baggage &bag)
{
FxVMFunctionCall *call;
// Make the action name lowercase
strlwr (sc.String);
call = DoActionSpecials(sc, state, bag);
if (call != NULL)
{
return call;
}
PFunction *afd = dyn_cast<PFunction>(bag.Info->Symbols.FindSymbol(FName(sc.String, true), true));
if (afd != NULL)
{
FArgumentList *args = new FArgumentList;
ParseFunctionParameters(sc, bag.Info, *args, afd, statestring, &bag.statedef);
call = new FxVMFunctionCall(afd, args->Size() > 0 ? args : NULL, sc);
if (args->Size() == 0)
{
delete args;
}
return call;
}
sc.ScriptError("Invalid state parameter %s\n", sc.String);
return NULL;
}
//==========================================================================
//
// ParseFunctionParameters
//
// Parses the parameters for a VM function. Called by both ParseStates
// (which will set statestring and statedef) and by ParseExpression0 (which
// will not set them). The first token returned by the scanner when entering
// this function should be '('.
//
//==========================================================================
void ParseFunctionParameters(FScanner &sc, PClassActor *cls, TArray<FxExpression *> &out_params,
PFunction *afd, FString statestring, FStateDefinitions *statedef)
{
const TArray<PType *> &params = afd->Variants[0].Implementation->Proto->ArgumentTypes;
const TArray<DWORD> &paramflags = afd->Variants[0].ArgFlags;
int numparams = (int)params.Size();
int pnum = 0;
bool zeroparm;
if (afd->Flags & VARF_Method)
{
numparams--;
pnum++;
}
if (afd->Flags & VARF_Action)
{
numparams -= 2;
pnum += 2;
}
assert(numparams >= 0);
zeroparm = numparams == 0;
if (numparams > 0 && !(paramflags[pnum] & VARF_Optional))
{
sc.MustGetStringName("(");
}
else
{
if (!sc.CheckString("("))
{
return;
}
}
while (numparams > 0)
{
FxExpression *x;
if (statedef != NULL && params[pnum] == TypeState && sc.CheckNumber())
{
// Special case: State label as an offset
if (sc.Number > 0 && statestring.Len() > 1)
{
sc.ScriptError("You cannot use state jumps commands with a jump offset on multistate definitions\n");
}
int v = sc.Number;
if (v < 0)
{
sc.ScriptError("Negative jump offsets are not allowed");
}
if (v > 0)
{
x = new FxStateByIndex(statedef->GetStateCount() + v, sc);
}
else
{
x = new FxConstant((FState*)NULL, sc);
}
}
else
{
// Use the generic parameter parser for everything else
x = ParseParameter(sc, cls, params[pnum], false);
}
out_params.Push(new FxParameter(x));
pnum++;
numparams--;
if (numparams > 0)
{
if (params[pnum] == NULL)
{ // varargs function
if (sc.CheckString(")"))
{
return;
}
pnum--;
numparams++;
}
else if ((paramflags[pnum] & VARF_Optional) && sc.CheckString(")"))
{
return;
}
sc.MustGetStringName (",");
}
}
if (zeroparm)
{
if (!sc.CheckString(")"))
{
sc.ScriptError("You cannot pass parameters to '%s'\n", afd->SymbolName.GetChars());
}
}
else
{
sc.MustGetStringName(")");
}
}
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