module forth
-currentLine = ""
-currentPos = 0
+# VM mem size
+size_mem = 1000000 # 1 mega-int
-function nextLine()
- if eof(STDIN)
- return false
- else
- currentLine = readLine()
- currentPos = 1
- return true
+# Buffer sizes
+size_RS = 1000 # Return stack size
+size_PS = 1000 # Parameter stack size
+size_TIB = 1000 # Terminal input buffer size
+
+# The mem array constitutes the memory of the VM. It has the following geography:
+#
+# mem = +-----------------------+
+# | Built-in Variables |
+# +-----------------------+
+# | Return Stack |
+# +-----------------------+
+# | Parameter Stack |
+# +-----------------------+
+# | Terminal Input Buffer |
+# +-----------------------+
+# | Dictionary |
+# +-----------------------+
+#
+# Note that all words (user-defined, primitive, variables, etc) are included in
+# the dictionary.
+#
+# Simple linear addressing is used with one exception: references to primitive code
+# blocks, which are represented as anonymous functions, appear as negative indicies
+# into the primitives array which contains these functions.
+
+mem = Array{Int64,1}(size_mem)
+primitives = Array{Function,1}()
+primNames = Array{ASCIIString,1}()
+
+# Built-in variables
+
+nextVarAddr = 1
+RSP0 = nextVarAddr; nextVarAddr += 1
+PSP0 = nextVarAddr; nextVarAddr += 1
+HERE = nextVarAddr; nextVarAddr += 1
+LATEST = nextVarAddr; nextVarAddr += 1
+
+mem[RSP0] = nextVarAddr # bottom of RS
+mem[PSP0] = mem[RSP0] + size_RS # bottom of PS
+TIB = mem[PSP0] + size_PS # address of terminal input buffer
+mem[HERE] = TIB + size_TIB # location of bottom of dictionary
+mem[LATEST] = 0 # no previous definition
+
+DICT = mem[HERE] # Save bottom of dictionary as constant
+
+# VM registers
+type Reg
+ RSP::Int64 # Return stack pointer
+ PSP::Int64 # Parameter/data stack pointer
+ IP::Int64 # Instruction pointer
+ W::Int64 # Working register
+end
+reg = Reg(mem[RSP0], mem[PSP0], 0, 0)
+
+# Stack manipulation functions
+
+type ParamStackUnderflow <: Exception end
+type ReturnStackUnderflow <: Exception end
+
+Base.showerror(io::IO, ex::ParamStackUnderflow) = print(io, "Parameter stack underflow.")
+Base.showerror(io::IO, ex::ReturnStackUnderflow) = print(io, "Return stack underflow.")
+
+getRSDepth() = reg.RSP - mem[RSP0]
+getPSDepth() = reg.PSP - mem[PSP0]
+
+function ensurePSDepth(depth::Int64)
+ if getPSDepth()<depth
+ throw(ParamStackUnderflow())
end
end
-function readPattern(pattern::Regex)
- m = match(pattern, currentLine)
- pos += length(m.match)
- return m.match
+function ensureRSDepth(depth::Int64)
+ if getRSDepth()<depth
+ throw(ReturnStackUnderflow())
+ end
+end
+
+function pushRS(val::Int64)
+ mem[reg.RSP+=1] = val
end
-modes = Dict{AbstractString,Function}()
-mode = ""
+function popRS()
+ ensureRSDepth(1)
-function interpretPrimitive()
- if haskey(dict, word)
- dict[word]()
- return true
- else
- return false
+ val = mem[reg.RSP]
+ reg.RSP -= 1
+ return val
end
-interpretNonPrimitive() = false
-interpretNumber() = false
-modes["interpret"] = () -> begin
- getWord()
+function pushPS(val::Int64)
+ mem[reg.PSP += 1] = val
+end
+
+function popPS()
+ ensurePSDepth(1)
+
+ val = mem[reg.PSP]
+ reg.PSP -= 1
+ return val
+end
+
+# Handy functions for adding/retrieving strings to/from memory.
+
+getString(addr::Int64, len::Int64) = ASCIIString([Char(c) for c in mem[addr:(addr+len-1)]])
+function putString(str::ASCIIString, addr::Int64)
+ mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
+end
+
+# Primitive creation and calling functions
+
+function defPrim(f::Function; name="nameless")
+ push!(primitives, f)
+ push!(primNames, replace(replace(name, "\004", "EOF"), "\n", "\\n"))
+
+ return -length(primitives)
+end
+
+callPrim(addr::Int64) = primitives[-addr]()
+
+# Word creation functions
+
+function createHeader(name::AbstractString, flags::Int64)
+ mem[mem[HERE]] = mem[LATEST]
+ mem[LATEST] = mem[HERE]
+ mem[HERE] += 1
+
+ mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
+ putString(name, mem[HERE]); mem[HERE] += length(name)
+end
+
+function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
+ createHeader(name, flags)
+
+ codeWordAddr = mem[HERE]
+ mem[codeWordAddr] = defPrim(f, name=name)
+ mem[HERE] += 1
+
+ return codeWordAddr
+end
+
+function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
+ createHeader(name, flags)
+
+ addr = mem[HERE]
+ mem[mem[HERE]] = DOCOL
+ mem[HERE] += 1
+
+ for wordAddr in wordAddrs
+ mem[mem[HERE]] = wordAddr
+ mem[HERE] += 1
+ end
+
+ return addr
+end
+
+# Variable creation functions
+
+function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
+
+ defPrimWord(name, eval(:(() -> begin
+ pushPS($(varAddr))
+ return NEXT
+ end)))
+end
+
+function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
+ createHeader(name, flags)
- if ! (interpretPrimitive() ||
- interpretNonPrimitive() ||
- interpretNumber())
- println("Error: unknown word '$word'.")
+ codeWordAddr = mem[HERE]
+ varAddr = mem[HERE] + 1
+
+ mem[mem[HERE]] = DOVAR; mem[HERE] += 1
+ mem[mem[HERE]] = initial; mem[HERE] += 1
+
+ return varAddr, codeWordAddr
+end
+
+function defConst(name::AbstractString, val::Int64; flags::Int64=0)
+ createHeader(name, flags)
+
+ mem[mem[HERE]] = DOCON; mem[HERE] += 1
+ mem[mem[HERE]] = val; mem[HERE] += 1
+
+ return val
+end
+
+# Threading Primitives (inner interpreter)
+
+NEXT = defPrim(() -> begin
+ reg.W = mem[reg.IP]
+ reg.IP += 1
+ return mem[reg.W]
+end, name="NEXT")
+
+DOCOL = defPrim(() -> begin
+ pushRS(reg.IP)
+ reg.IP = reg.W + 1
+ return NEXT
+end, name="DOCOL")
+
+DOVAR = defPrim(() -> begin
+ pushPS(reg.W + 1)
+ return NEXT
+end, name="DOVAR")
+
+DOCON = defPrim(() -> begin
+ pushPS(mem[reg.W + 1])
+ return NEXT
+end, name="DOVAR")
+
+EXIT = defPrimWord("EXIT", () -> begin
+ reg.IP = popRS()
+ return NEXT
+end)
+
+# Dictionary entries for core built-in variables, constants
+
+HERE_CFA = defExistingVar("HERE", HERE)
+LATEST_CFA = defExistingVar("LATEST", LATEST)
+PSP0_CFA = defExistingVar("PSP0", PSP0)
+RSP0_CFA = defExistingVar("RSP0", RSP0)
+
+defConst("DOCOL", DOCOL)
+defConst("DOCON", DOCON)
+defConst("DOVAR", DOVAR)
+
+defConst("DICT", DICT)
+defConst("MEMSIZE", size_mem)
+
+F_IMMED = defConst("F_IMMED", 128)
+F_HIDDEN = defConst("F_HIDDEN", 256)
+F_LENMASK = defConst("F_LENMASK", 127)
+
+# Basic forth primitives
+
+DROP = defPrimWord("DROP", () -> begin
+ popPS()
+ return NEXT
+end)
+
+SWAP = defPrimWord("SWAP", () -> begin
+ a = popPS()
+ b = popPS()
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
+
+DUP = defPrimWord("DUP", () -> begin
+ ensurePSDepth(1)
+ pushPS(mem[reg.PSP])
+ return NEXT
+end)
+
+OVER = defPrimWord("OVER", () -> begin
+ ensurePSDepth(2)
+ pushPS(mem[reg.PSP-1])
+ return NEXT
+end)
+
+ROT = defPrimWord("ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(c)
+ return NEXT
+end)
+
+NROT = defPrimWord("-ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(a)
+ pushPS(c)
+ pushPS(b)
+ return NEXT
+end)
+
+
+TWODROP = defPrimWord("2DROP", () -> begin
+ popPS()
+ popPS()
+ return NEXT
+end)
+
+TWODUP = defPrimWord("2DUP", () -> begin
+ ensurePSDepth(2)
+ a = mem[reg.PSP-1]
+ b = mem[reg.PSP]
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
+
+TWOSWAP = defPrimWord("2SWAP", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ d = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(d)
+ pushPS(c)
+ return NEXT
+end)
+
+TWOOVER = defPrimWord("2OVER", () -> begin
+ ensurePSDepth(4)
+ a = mem[reg.PSP-3]
+ b = mem[reg.PSP-2]
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
+
+QDUP = defPrimWord("?DUP", () -> begin
+ ensurePSDepth(1)
+ val = mem[reg.PSP]
+ if val != 0
+ pushPS(val)
+ end
+ return NEXT
+end)
+
+INCR = defPrimWord("1+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 1
+ return NEXT
+end)
+
+DECR = defPrimWord("1-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 1
+ return NEXT
+end)
+
+INCR2 = defPrimWord("2+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 2
+ return NEXT
+end)
+
+DECR2 = defPrimWord("2-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 2
+ return NEXT
+end)
+
+ADD = defPrimWord("+", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a+b)
+ return NEXT
+end)
+
+SUB = defPrimWord("-", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a-b)
+ return NEXT
+end)
+
+MUL = defPrimWord("*", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a*b)
+ return NEXT
+end)
+
+DIVMOD = defPrimWord("/MOD", () -> begin
+ b = popPS()
+ a = popPS()
+ q,r = divrem(a,b)
+ pushPS(r)
+ pushPS(q)
+ return NEXT
+end)
+
+TWOMUL = defPrimWord("2*", () -> begin
+ pushPS(popPS() << 1)
+ return NEXT
+end)
+
+TWODIV = defPrimWord("2/", () -> begin
+ pushPS(popPS() >> 1)
+ return NEXT
+end)
+
+EQU = defPrimWord("=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a==b ? -1 : 0)
+ return NEXT
+end)
+
+NEQU = defPrimWord("<>", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a!=b ? -1 : 0)
+ return NEXT
+end)
+
+LT = defPrimWord("<", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<b ? -1 : 0)
+ return NEXT
+end)
+
+GT = defPrimWord(">", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>b ? -1 : 0)
+ return NEXT
+end)
+
+LE = defPrimWord("<=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<=b ? -1 : 0)
+ return NEXT
+end)
+
+GE = defPrimWord(">=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>=b ? -1 : 0)
+ return NEXT
+end)
+
+ZEQU = defPrimWord("0=", () -> begin
+ pushPS(popPS() == 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZNEQU = defPrimWord("0<>", () -> begin
+ pushPS(popPS() != 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZLT = defPrimWord("0<", () -> begin
+ pushPS(popPS() < 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZGT = defPrimWord("0>", () -> begin
+ pushPS(popPS() > 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZLE = defPrimWord("0<=", () -> begin
+ pushPS(popPS() <= 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZGE = defPrimWord("0>=", () -> begin
+ pushPS(popPS() >= 0 ? -1 : 0)
+ return NEXT
+end)
+
+AND = defPrimWord("AND", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a & b)
+ return NEXT
+end)
+
+OR = defPrimWord("OR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a | b)
+ return NEXT
+end)
+
+XOR = defPrimWord("XOR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a $ b)
+ return NEXT
+end)
+
+INVERT = defPrimWord("INVERT", () -> begin
+ pushPS(~popPS())
+ return NEXT
+end)
+
+# Literals
+
+LIT = defPrimWord("LIT", () -> begin
+ pushPS(mem[reg.IP])
+ reg.IP += 1
+ return NEXT
+end)
+
+# Memory primitives
+
+STORE = defPrimWord("!", () -> begin
+ addr = popPS()
+ dat = popPS()
+ mem[addr] = dat
+ return NEXT
+end)
+
+FETCH = defPrimWord("@", () -> begin
+ addr = popPS()
+ pushPS(mem[addr])
+ return NEXT
+end)
+
+ADDSTORE = defPrimWord("+!", () -> begin
+ addr = popPS()
+ toAdd = popPS()
+ mem[addr] += toAdd
+ return NEXT
+end)
+
+SUBSTORE = defPrimWord("-!", () -> begin
+ addr = popPS()
+ toSub = popPS()
+ mem[addr] -= toSub
+ return NEXT
+end)
+
+
+# Return Stack
+
+TOR = defPrimWord(">R", () -> begin
+ pushRS(popPS())
+ return NEXT
+end)
+
+FROMR = defPrimWord("R>", () -> begin
+ pushPS(popRS())
+ return NEXT
+end)
+
+RFETCH = defPrimWord("R@", () -> begin
+ pushPS(mem[reg.RSP])
+ return NEXT
+end)
+
+RSPFETCH = defPrimWord("RSP@", () -> begin
+ pushPS(reg.RSP)
+ return NEXT
+end)
+
+RSPSTORE = defPrimWord("RSP!", () -> begin
+ RSP = popPS()
+ return NEXT
+end)
+
+RDROP = defPrimWord("RDROP", () -> begin
+ popRS()
+ return NEXT
+end)
+
+# Parameter Stack
+
+PSPFETCH = defPrimWord("PSP@", () -> begin
+ pushPS(reg.PSP)
+ return NEXT
+end)
+
+PSPSTORE = defPrimWord("PSP!", () -> begin
+ PSP = popPS()
+ return NEXT
+end)
+
+# Working Register
+
+WFETCH = defPrimWord("W@", () -> begin
+ pushPS(reg.W)
+ return NEXT
+end)
+
+WSTORE = defPrimWord("W!", () -> begin
+ reg.W = popPS()
+ return NEXT
+end)
+
+# I/O
+
+sources = Array{Any,1}()
+currentSource() = sources[length(sources)]
+
+defConst("TIB", TIB)
+NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
+TOIN, TOIN_CFA = defNewVar(">IN", 0)
+EOF = defConst("EOF", 4)
+
+KEY = defPrimWord("KEY", () -> begin
+ if mem[TOIN] >= mem[NUMTIB]
+ mem[TOIN] = 0
+
+ if !eof(currentSource())
+ line = readline(currentSource())
+ mem[NUMTIB] = length(line)
+ putString(line, TIB)
+ else
+ mem[NUMTIB] = 1
+ mem[TIB] = EOF
+ end
end
+
+ pushPS(mem[TIB + mem[TOIN]])
+ mem[TOIN] += 1
+
+ return NEXT
+end)
+
+EMIT = defPrimWord("EMIT", () -> begin
+ print(Char(popPS()))
+ return NEXT
+end)
+
+WORD = defPrimWord("WORD", () -> begin
+
+ eof_char = Char(EOF)
+ c = eof_char
+
+ while true
+ callPrim(mem[KEY])
+ c = Char(popPS())
+
+ if c == ' ' || c == '\t'
+ continue
+ end
+
+ break
+ end
+
+ wordAddr = mem[HERE]
+ offset = 0
+
+ if c == '\n' || c == eof_char
+ # Treat newline as a special word
+
+ mem[wordAddr + offset] = Int64(c)
+ pushPS(wordAddr)
+ pushPS(1)
+ return NEXT
+ end
+
+ while true
+ mem[wordAddr + offset] = Int64(c)
+ offset += 1
+
+ callPrim(mem[KEY])
+ c = Char(popPS())
+
+ if c == ' ' || c == '\t' || c == '\n' || c == eof_char
+ # Rewind KEY
+ mem[TOIN] -= 1
+ break
+ end
+ end
+
+ wordLen = offset
+
+ pushPS(wordAddr)
+ pushPS(wordLen)
+
+ return NEXT
+end)
+
+BASE, BASE_CFA = defNewVar("BASE", 10)
+NUMBER = defPrimWord("NUMBER", () -> begin
+
+ wordLen = popPS()
+ wordAddr = popPS()
+
+ s = getString(wordAddr, wordLen)
+
+ try
+ pushPS(parse(Int64, s, mem[BASE]))
+ pushPS(0)
+ catch
+ pushPS(1) # Error indication
+ end
+
+ return NEXT
+end)
+
+# Dictionary searches
+
+FIND = defPrimWord("FIND", () -> begin
+
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = lowercase(getString(wordAddr, wordLen))
+
+ latest = LATEST
+
+ i = 0
+ while (latest = mem[latest]) > 0
+ lenAndFlags = mem[latest+1]
+ len = lenAndFlags & F_LENMASK
+ hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
+
+ if hidden || len != wordLen
+ continue
+ end
+
+ thisAddr = latest+2
+ thisWord = lowercase(getString(thisAddr, len))
+
+ if lowercase(thisWord) == lowercase(word)
+ break
+ end
+ end
+
+ pushPS(latest)
+
+ return NEXT
+end)
+
+TOCFA = defPrimWord(">CFA", () -> begin
+
+ addr = popPS()
+ lenAndFlags = mem[addr+1]
+ len = lenAndFlags & F_LENMASK
+
+ pushPS(addr + 2 + len)
+
+ return NEXT
+end)
+
+TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
+
+# Branching
+
+BRANCH = defPrimWord("BRANCH", () -> begin
+ reg.IP += mem[reg.IP]
+ return NEXT
+end)
+
+ZBRANCH = defPrimWord("0BRANCH", () -> begin
+ if (popPS() == 0)
+ reg.IP += mem[reg.IP]
+ else
+ reg.IP += 1
+ end
+
+ return NEXT
+end)
+
+# Compilation
+
+STATE, STATE_CFA = defNewVar("STATE", 0)
+
+HEADER = defPrimWord("HEADER", () -> begin
+
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = getString(wordAddr, wordLen)
+
+ createHeader(word, 0)
+
+ return NEXT
+end)
+
+COMMA = defPrimWord(",", () -> begin
+ mem[mem[HERE]] = popPS()
+ mem[HERE] += 1
+
+ return NEXT
+end)
+
+LBRAC = defPrimWord("[", () -> begin
+ mem[STATE] = 0
+ return NEXT
+end, flags=F_IMMED)
+
+RBRAC = defPrimWord("]", () -> begin
+ mem[STATE] = 1
+ return NEXT
+end, flags=F_IMMED)
+
+HIDDEN = defPrimWord("HIDDEN", () -> begin
+ addr = popPS() + 1
+ mem[addr] = mem[addr] $ F_HIDDEN
+ return NEXT
+end)
+
+HIDE = defWord("HIDE",
+ [WORD,
+ FIND,
+ HIDDEN,
+ EXIT])
+
+COLON = defWord(":",
+ [WORD,
+ HEADER,
+ LIT, DOCOL, COMMA,
+ LATEST_CFA, FETCH, HIDDEN,
+ RBRAC,
+ EXIT])
+
+SEMICOLON = defWord(";",
+ [LIT, EXIT, COMMA,
+ LATEST_CFA, FETCH, HIDDEN,
+ LBRAC,
+ EXIT], flags=F_IMMED)
+
+IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
+ lenAndFlagsAddr = mem[LATEST] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
+ return NEXT
+end, flags=F_IMMED)
+
+TICK = defWord("'",
+ [WORD, FIND, TOCFA, EXIT])
+
+BTICK = defWord("[']",
+ [FROMR, DUP, INCR, TOR, FETCH, EXIT])
+
+# CREATE and DOES>
+
+CREATE = defWord("CREATE",
+ [WORD,
+ HEADER,
+ LIT, DOVAR, COMMA, EXIT]);
+
+DODOES = defPrim(() -> begin
+ pushRS(reg.IP)
+ reg.IP = reg.W + 1
+ return NEXT
+end, name="DOCOL")
+
+defConst("DODOES", DODOES)
+
+FROMDOES_PAREN = defWord("(DOES>)",
+ [DODOES, LATEST, FETCH, TOCFA, STORE, EXIT])
+
+FROMDOES = defWord("DOES>",
+ [BTICK, FROMDOES_PAREN, COMMA, BTICK, EXIT, COMMA,
+ BTICK, LIT, COMMA, LATEST, FETCH, TODFA, COMMA], flags=F_IMMED)
+
+
+# Strings
+
+LITSTRING = defPrimWord("LITSTRING", () -> begin
+ len = mem[reg.IP]
+ reg.IP += 1
+ pushPS(reg.IP)
+ pushPS(len)
+ reg.IP += len
+
+ return NEXT
+end)
+
+TELL = defPrimWord("TELL", () -> begin
+ len = popPS()
+ addr = popPS()
+ str = getString(addr, len)
+ print(str)
+ return NEXT
+end)
+
+# Outer interpreter
+
+EXECUTE = defPrimWord("EXECUTE", () -> begin
+ reg.W = popPS()
+ return mem[reg.W]
+end)
+
+type ParseError <: Exception
+ wordName::ASCIIString
end
+Base.showerror(io::IO, ex::ParseError) = print(io, "Parse error at word: '$(ex.wordName)'.")
-function repl()
+DEBUG, DEBUG_CFA = defNewVar("DEBUG", 0)
- mode = "interpret"
- while mode != "stop"
- modes[mode]()
+INTERPRET = defPrimWord("INTERPRET", () -> begin
+
+ callPrim(mem[WORD])
+
+ wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
+ if mem[DEBUG] != 0
+ println("... ", replace(replace(wordName, "\004", "EOF"), "\n", "\\n"), " ...")
+ end
+
+ callPrim(mem[TWODUP])
+ callPrim(mem[FIND])
+
+ wordAddr = mem[reg.PSP]
+
+ if wordAddr>0
+ # Word in dictionary
+
+ isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
+ callPrim(mem[TOCFA])
+
+ callPrim(mem[NROT]) # get rid of extra copy of word string details
+ popPS()
+ popPS()
+
+ if mem[STATE] == 0 || isImmediate
+ # Execute!
+ return callPrim(mem[EXECUTE])
+ else
+ # Append CFA to dictionary
+ callPrim(mem[COMMA])
+ end
+ else
+ # Not in dictionary, assume number
+
+ popPS()
+
+ callPrim(mem[NUMBER])
+
+ if popPS() != 0
+ throw(ParseError(wordName))
+ end
+
+ if mem[STATE] == 0
+ # Number already on stack!
+ else
+ # Append literal to dictionary
+ pushPS(LIT)
+ callPrim(mem[COMMA])
+ callPrim(mem[COMMA])
+ end
+ end
+
+ return NEXT
+end)
+
+QUIT = defWord("QUIT",
+ [RSP0_CFA, RSPSTORE,
+ INTERPRET,
+ BRANCH,-2])
+
+BYE = defPrimWord("BYE", () -> begin
+ return 0
+end)
+
+PROMPT = defPrimWord("PROMPT", () -> begin
+ println(" ok")
+end)
+
+NL = defPrimWord("\n", () -> begin
+ if mem[STATE] == 0 && currentSource() == STDIN
+ callPrim(mem[PROMPT])
+ end
+ return NEXT
+end, flags=F_IMMED)
+
+INCLUDE = defPrimWord("INCLUDE", () -> begin
+ callPrim(mem[WORD])
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = getString(wordAddr, wordLen)
+
+ push!(sources, open(word, "r"))
+
+ # Clear input buffer
+ mem[NUMTIB] = 0
+
+ return NEXT
+end)
+
+EOF_WORD = defPrimWord("\x04", () -> begin
+ if currentSource() != STDIN
+ close(currentSource())
+ end
+
+ pop!(sources)
+
+ if length(sources)>0
+ if currentSource() == STDIN
+ callPrim(mem[PROMPT])
+ end
+
+ return NEXT
+ else
+ return 0
+ end
+end, flags=F_IMMED)
+
+# Odds and Ends
+
+CHAR = defPrimWord("CHAR", () -> begin
+ callPrim(mem[WORD])
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = getString(wordAddr, wordLen)
+ pushPS(Int64(word[1]))
+
+ return NEXT
+end)
+
+initialized = false
+initFileName = nothing
+if isfile("lib.4th")
+ initFileName = "lib.4th"
+elseif isfile(Pkg.dir("forth/src/lib.4th"))
+ initFileName = Pkg.dir("forth/src/lib.4th")
+end
+
+
+#### VM loop ####
+function run(;initialize=true)
+ # Begin with STDIN as source
+ push!(sources, STDIN)
+
+ global initialized, initFileName
+ if !initialized && initialize
+ if initFileName != nothing
+ print("Including definitions from $initFileName...")
+ push!(sources, open(initFileName, "r"))
+ initialized = true
+ else
+ println("No library file found. Only primitive words available.")
+ end
+ end
+
+ # Start with IP pointing to first instruction of outer interpreter
+ reg.IP = QUIT + 1
+
+ # Primitive processing loop.
+ # Everyting else is simply a consequence of this loop!
+ jmp = NEXT
+ while jmp != 0
+ try
+ if mem[DEBUG] != 0
+ println("Evaluating prim ", jmp," ", primNames[-jmp])
+ end
+
+ jmp = callPrim(jmp)
+
+ catch ex
+ showerror(STDOUT, ex)
+ println()
+
+ while !isempty(sources) && currentSource() != STDIN
+ close(pop!(sources))
+ end
+
+ mem[STATE] = 0
+ mem[NUMTIB] = 0
+ reg.PSP = mem[PSP0]
+ reg.RSP = mem[RSP0]
+ reg.IP = QUIT + 1
+ jmp = NEXT
+ end
end
end
+# Debugging tools
+
+function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
+ chars = Array{Char,1}(cellsPerLine)
+
+ lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
+ endAddr = startAddr + count - 1
+
+ q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
+ numLines = q + (r > 0 ? 1 : 0)
+
+ i = lineStartAddr
+ for l in 1:numLines
+ print(i,":")
+
+ for c in 1:cellsPerLine
+ if i >= startAddr && i <= endAddr
+ print("\t",mem[i])
+ if mem[i]>=32 && mem[i]<128
+ chars[c] = Char(mem[i])
+ else
+ chars[c] = '.'
+ end
+ else
+ print("\t")
+ chars[c] = ' '
+ end
+
+ i += 1
+ end
+
+ println("\t", ASCIIString(chars))
+ end
+end
+
+function printPS()
+ count = reg.PSP - mem[PSP0]
+
+ if count > 0
+ print("<$count>")
+ for i in (mem[PSP0]+1):reg.PSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Parameter stack empty")
+ end
+end
+
+function printRS()
+ count = reg.RSP - mem[RSP0]
+
+ if count > 0
+ print("<$count>")
+ for i in (mem[RSP0]+1):reg.RSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Return stack empty")
+ end
+end
+
+DUMP = defPrimWord("DUMP", () -> begin
+ count = popPS()
+ addr = popPS()
+
+ dump(addr, count=count)
+
+ return NEXT
+end)
+
end
The Lambda Lab / projects / forth.jl.git / blobdiff