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https://github.com/Sei-Lisa/LSL-PyOptimizer
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Remove the symbol table's parent pointer
Instead of a tree of symbol tables, we keep a running stack of active symbol tables while parsing. The only case in which this causes problems is forward reference resolution for jump labels, which is solved by storing a copy of the stack at the point the jump was found.
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Sei Lisa
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76f483fc11
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660dcff65b
1 changed files with 40 additions and 27 deletions
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@ -244,17 +244,20 @@ class parser(object):
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def PushScope(self):
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"""Create a new symbol table / scope level"""
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self.symtab.append({-1:self.scopeindex}) # Add parent pointer
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self.scopeindex = len(self.symtab)-1
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self.scopeindex = len(self.symtab)
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self.symtab.append({}) # Add new symbol table
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self.scopestack.append(self.scopeindex)
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def PopScope(self):
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"""Return to the previous scope level"""
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self.scopeindex = self.symtab[self.scopeindex][-1] # -1 is a dict key, not an index
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assert self.scopeindex is not None, 'Unexpected internal error'
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assert self.scopeindex == self.scopestack[-1]
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self.scopestack.pop()
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self.scopeindex = self.scopestack[-1]
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assert len(self.scopestack) > 0
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def AddSymbol(self, kind, scope, name, **values):
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values['Kind'] = kind
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if kind in 'vl':
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if kind in ('v', 'l'):
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values['Scope'] = scope
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self.symtab[scope][name] = values
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@ -278,33 +281,33 @@ class parser(object):
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gives an Name Not Defined error.
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"""
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scopelevel = self.scopeindex
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while scopelevel is not None:
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symtab = self.symtab[scopelevel]
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if symbol in symtab and (not MustBeLabel or symtab[symbol]['Kind'] == 'l'):
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scopelevel = len(self.scopestack)
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while scopelevel:
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scopelevel -= 1
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symtab = self.symtab[self.scopestack[scopelevel]]
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if symbol in symtab and (not MustBeLabel
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or symtab[symbol]['Kind'] == 'l'):
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return symtab[symbol]
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scopelevel = symtab[-1] # -1 is a dict key, not an index
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return None
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# No labels or states allowed here (but functions are)
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def FindSymbolFull(self, symbol, scopelevel = None):
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def FindSymbolFull(self, symbol, globalonly=False):
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"""Returns the symbol table entry for the given symbol."""
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if scopelevel is None:
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# unspecified scope level means to look in the current scope
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scopelevel = self.scopeindex
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while scopelevel: # Loop over all local scopes
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symtab = self.symtab[scopelevel]
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scopelevel = 1 if globalonly else len(self.scopestack)
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while scopelevel: # Loop over all scopes in the stack
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scopelevel -= 1
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symtab = self.symtab[self.scopestack[scopelevel]]
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if symbol in symtab:
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# This can't happen, as functions can't be local
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#if len(symtab[symbol]) > 3:
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# return (symtab[symbol][1], symtab[symbol][3])
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return symtab[symbol]
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scopelevel = symtab[-1]
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try:
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return self.symtab[0][symbol] # Quick guess
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except KeyError:
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if self.disallowglobalvars and symbol not in self.symtab[0] \
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or symbol not in self.globals:
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if (self.disallowglobalvars and symbol not in self.symtab[0]
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or symbol not in self.globals
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):
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return None # Disallow forwards in global var mode
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return self.globals[symbol]
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@ -947,7 +950,7 @@ class parser(object):
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self.NextToken()
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# Functions are looked up in the global scope only.
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sym = self.FindSymbolFull(val, 0)
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sym = self.FindSymbolFull(val, globalonly=True)
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if sym is None:
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self.errorpos = savepos
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raise EParseUndefined(self)
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@ -1325,7 +1328,7 @@ list lazy_list_set(list L, integer i, list v)
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if typ not in self.TypeToExtractionFunction:
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raise EParseNoConversion(self)
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fn = self.TypeToExtractionFunction[typ]
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sym = self.FindSymbolFull(fn, 0)
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sym = self.FindSymbolFull(fn, globalonly=True)
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assert sym is not None
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fnparamtypes = sym['ParamTypes']
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subparamtypes = [x.t for x in expr.ch]
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@ -1747,8 +1750,8 @@ list lazy_list_set(list L, integer i, list v)
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if not sym or sym['Kind'] != 'l':
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# It might still be a forward reference, so we add it to the
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# list of things to look up when done
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self.jump_lookups.append((name, self.scopeindex, self.errorpos,
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jumpnode))
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self.jump_lookups.append((name, self.scopestack[:],
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self.errorpos, jumpnode))
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else:
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jumpnode.scope = sym['Scope']
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sym['ref'] += 1
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@ -2568,9 +2571,12 @@ list lazy_list_set(list L, integer i, list v)
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self.Parse_states()
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self.expect('EOF')
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assert len(self.scopestack) == 1 and self.scopestack[0] == 0
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# Check the pending jump targets to assign them the scope of the label.
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for tgt in self.jump_lookups:
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self.scopeindex = tgt[1]
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self.scopestack = tgt[1]
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self.scopeindex = self.scopestack[-1]
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sym = self.FindSymbolPartial(tgt[0], MustBeLabel = True)
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if sym is None:
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self.errorpos = tgt[2]
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@ -2579,6 +2585,7 @@ list lazy_list_set(list L, integer i, list v)
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sym['ref'] += 1
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del self.jump_lookups # Finished with it.
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self.scopestack = [0]
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def Parse_single_expression(self):
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"""Parse the script as an expression, Used by lslcalc.
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@ -2825,13 +2832,14 @@ list lazy_list_set(list L, integer i, list v)
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# Symbol table:
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# This is a list of all local and global symbol tables.
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# The first element (0) is the global scope. Each symbol table is a
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# dictionary. Element -1 of the dictionary is the parent index. The
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# rest of entries are dictionaries. Each has a 'Kind', which can be
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# dictionary of symbols, whose elements are in turn dictionaries of
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# attributes. Each has a 'Kind', which can be:
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# 'v' for variable, 'f' for function, 'l' for label, 's' for state,
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# or 'e' for event. Some have a 'Loc' indicating the location (index)
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# of the definition in the tree root.
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# Variables have 'Scope' and 'Type' (a string).
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# Global variables also have 'Loc'.
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# Variables that are parameters also have 'Param'.
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# Functions have 'Type' (return type, a string) and 'ParamTypes' (a list of strings).
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# User-defined functions also have 'Loc' and 'ParamNames' (a list of strings).
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# Labels only have 'Scope'.
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@ -2841,9 +2849,13 @@ list lazy_list_set(list L, integer i, list v)
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# Incorporate the library into the initial symbol table.
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self.symtab = [self.funclibrary.copy()]
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self.symtab[0][-1] = None
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# Current scope index
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self.scopeindex = 0
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# Stack of scopes in which to look for a symbol as we parse
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self.scopestack = [0]
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if self.prettify:
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# Add the constants as symbol table variables...
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for i in self.constants:
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@ -2915,6 +2927,7 @@ list lazy_list_set(list L, integer i, list v)
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# No longer needed. The data is already in self.symtab[0].
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del self.globals
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del self.scopestack
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treesymtab = self.tree, self.symtab
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del self.tree
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