+SPAN, SPAN_CFA = defNewVar("SPAN", 0)
+EXPECT_CFA = defPrimWord("EXPECT", () -> begin
+ maxLen = popPS()
+ addr = popPS()
+
+ if currentSource() == STDIN
+ line = getLineFromSTDIN()
+ else
+ if !eof(currentSource())
+ line = chomp(readline(currentSource()))
+ else
+ line = "\x04" # eof
+ end
+ end
+
+ mem[SPAN] = min(length(line), maxLen)
+ putString(line[1:mem[SPAN]], addr)
+
+ return NEXT
+end)
+
+BASE, BASE_CFA = defNewVar("BASE", 10)
+NUMBER_CFA = defPrimWord("NUMBER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+
+ s = getString(wordAddr, wordLen)
+
+ pushPS(parse(Int64, s, mem[BASE]))
+
+ return NEXT
+end)
+
+# Dictionary searches
+
+TOCFA_CFA = defPrimWord(">CFA", () -> begin
+
+ addr = popPS()
+ lenAndFlags = mem[addr+1]
+ len = lenAndFlags & F_LENMASK
+
+ pushPS(addr + 2 + len)
+
+ return NEXT
+end)
+
+TOBODY_CFA = defWord(">BODY", [INCR_CFA, EXIT_CFA])
+
+FIND_CFA = defPrimWord("FIND", () -> begin
+
+ countedAddr = popPS()
+ wordAddr = countedAddr + 1
+ wordLen = mem[countedAddr]
+ word = lowercase(getString(wordAddr, wordLen))
+
+ latest = LATEST
+ lenAndFlags = 0
+
+ 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
+
+ if latest > 0
+ pushPS(latest)
+ callPrim(mem[TOCFA_CFA])
+ if (lenAndFlags & F_IMMED) == F_IMMED
+ pushPS(1)
+ else
+ pushPS(-1)
+ end
+ else
+ pushPS(countedAddr)
+ pushPS(0)
+ end
+
+ return NEXT
+end)
+
+
+# Branching
+
+BRANCH_CFA = defPrimWord("BRANCH", () -> begin
+ reg.IP += mem[reg.IP]
+ return NEXT
+end)
+
+ZBRANCH_CFA = defPrimWord("0BRANCH", () -> begin
+ if (popPS() == 0)
+ reg.IP += mem[reg.IP]
+ else
+ reg.IP += 1
+ end
+
+ return NEXT
+end)
+
+# Strings
+
+LITSTRING_CFA = defPrimWord("LITSTRING", () -> begin
+ len = mem[reg.IP]
+ reg.IP += 1
+ pushPS(reg.IP)
+ pushPS(len)
+ reg.IP += len
+
+ return NEXT
+end)
+
+TYPE_CFA = defPrimWord("TYPE", () -> begin
+ len = popPS()
+ addr = popPS()
+ str = getString(addr, len)
+ print(str)
+ return NEXT
+end)
+
+# Interpreter/Compiler-specific I/O
+
+TIB_CFA = defConst("TIB", TIB)
+NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
+TOIN, TOIN_CFA = defNewVar(">IN", 0)
+
+QUERY_CFA = defWord("QUERY",
+ [TIB_CFA, LIT_CFA, 160, EXPECT_CFA,
+ SPAN_CFA, FETCH_CFA, NUMTIB_CFA, STORE_CFA,
+ LIT_CFA, 0, TOIN_CFA, STORE_CFA,
+ EXIT_CFA])
+
+WORD_CFA = defPrimWord("WORD", () -> begin
+ delim = popPS()
+
+ # Chew up initial occurrences of delim
+ while (mem[TOIN]<mem[NUMTIB] && mem[TIB+mem[TOIN]] == delim)
+ mem[TOIN] += 1
+ end
+
+ countAddr = mem[H]
+ addr = mem[H]+1
+
+ # Start reading in word
+ count = 0
+ while (mem[TOIN]<mem[NUMTIB])
+ mem[addr] = mem[TIB+mem[TOIN]]
+ mem[TOIN] += 1
+
+ if (mem[addr] == delim)
+ break
+ end
+
+ count += 1
+ addr += 1
+ end
+
+ # Record count
+ mem[countAddr] = count
+ pushPS(countAddr)
+
+ return NEXT
+end)
+
+# Compilation
+
+STATE, STATE_CFA = defNewVar("STATE", 0)
+
+COMMA_CFA = defPrimWord(",", () -> begin
+ mem[mem[H]] = popPS()
+ mem[H] += 1
+
+ return NEXT
+end)
+
+HERE_CFA = defWord("HERE",
+ [H_CFA, FETCH_CFA, EXIT_CFA])
+
+HEADER_CFA = defPrimWord("HEADER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
+
+ createHeader(word, 0)
+
+ return NEXT
+end)
+
+CREATE_CFA = defWord("CREATE",
+ [LIT_CFA, 32, WORD_CFA, HEADER_CFA,
+ LIT_CFA, DOVAR, COMMA_CFA,
+ EXIT_CFA])
+
+DODOES = defPrim(() -> begin
+ pushRS(reg.IP)
+ reg.IP = popPS()
+ pushPS(reg.W + 1)
+ return NEXT
+end, name="DODOES")
+
+DOES_HELPER_CFA = defPrimWord("(DOES>)", () -> begin
+
+ pushPS(mem[LATEST])
+ callPrim(mem[TOCFA_CFA])
+ cfa = popPS()
+
+ runtimeAddr = popPS()
+
+ mem[cfa] = defPrim(eval(:(() -> begin
+ pushPS($(runtimeAddr))
+ return DODOES
+ end)), name="doesPrim")
+
+ return NEXT
+end, flags=F_IMMED)
+
+DOES_CFA = defWord("DOES>",
+ [LIT_CFA, LIT_CFA, COMMA_CFA, HERE_CFA, LIT_CFA, 3, ADD_CFA, COMMA_CFA,
+ LIT_CFA, DOES_HELPER_CFA, COMMA_CFA, LIT_CFA, EXIT_CFA, COMMA_CFA, EXIT_CFA],
+ flags=F_IMMED)
+
+LBRAC_CFA = defPrimWord("[", () -> begin
+ mem[STATE] = 0
+ return NEXT
+end, flags=F_IMMED)
+
+RBRAC_CFA = defPrimWord("]", () -> begin
+ mem[STATE] = 1
+ return NEXT
+end, flags=F_IMMED)
+
+HIDDEN_CFA = defPrimWord("HIDDEN", () -> begin
+ lenAndFlagsAddr = mem[LATEST] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_HIDDEN
+ return NEXT
+end)
+
+COLON_CFA = defWord(":",
+ [LIT_CFA, 32, WORD_CFA,
+ HEADER_CFA,
+ LIT_CFA, DOCOL, COMMA_CFA,
+ HIDDEN_CFA,
+ RBRAC_CFA,
+ EXIT_CFA])
+
+SEMICOLON_CFA = defWord(";",
+ [LIT_CFA, EXIT_CFA, COMMA_CFA,
+ HIDDEN_CFA,
+ LBRAC_CFA,
+ EXIT_CFA], flags=F_IMMED)
+
+IMMEDIATE_CFA = defPrimWord("IMMEDIATE", () -> begin
+ lenAndFlagsAddr = mem[LATEST] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
+ return NEXT
+end, flags=F_IMMED)
+
+# Outer Interpreter
+
+EXECUTE_CFA = defPrimWord("EXECUTE", () -> begin
+ reg.W = popPS()
+ return mem[reg.W]
+end)
+
+INTERPRET_CFA = defWord("INTERPRET",
+ [LIT_CFA, 32, WORD_CFA, # Read next space-delimited word
+
+ DUP_CFA, FETCH_CFA, ZE_CFA, ZBRANCH_CFA, 3,
+ DROP_CFA, EXIT_CFA, # Exit if TIB is exhausted
+
+ STATE_CFA, FETCH_CFA, ZBRANCH_CFA, 24,
+ # Compiling
+ FIND_CFA, QDUP_CFA, ZBRANCH_CFA, 13,
+
+ # Found word.
+ LIT_CFA, -1, EQ_CFA, INVERT_CFA, ZBRANCH_CFA, 4,
+
+ # Immediate: Execute!
+ EXECUTE_CFA, BRANCH_CFA, -26,
+
+ # Not immediate: Compile!
+ COMMA_CFA, BRANCH_CFA, -29,
+
+ # No word found, parse number
+ NUMBER_CFA, LIT_CFA, LIT_CFA, COMMA_CFA, COMMA_CFA, BRANCH_CFA, -36,
+
+ # Interpreting
+ FIND_CFA, QDUP_CFA, ZBRANCH_CFA, 5,
+
+ # Found word. Execute!
+ DROP_CFA, EXECUTE_CFA, BRANCH_CFA, -44,
+
+ # No word found, parse number and leave on stack
+ NUMBER_CFA, BRANCH_CFA, -47,
+ EXIT_CFA])
+
+PROMPT_CFA = defPrimWord("PROMPT", () -> begin
+ if (mem[STATE] == 0 && currentSource() == STDIN)
+ println(" ok")
+ end
+
+ return NEXT
+end)
+
+QUIT_CFA = defWord("QUIT",
+ [LIT_CFA, 0, STATE_CFA, STORE_CFA,
+ LIT_CFA, 0, NUMTIB_CFA, STORE_CFA,
+ RSP0_CFA, RSPSTORE_CFA,
+ QUERY_CFA,
+ INTERPRET_CFA, PROMPT_CFA,
+ BRANCH_CFA,-4])
+
+ABORT_CFA = defWord("ABORT",
+ [PSP0_CFA, PSPSTORE_CFA, QUIT_CFA])
+
+BYE_CFA = defPrimWord("BYE", () -> begin
+ println("\nBye!")
+ return 0
+end)
+
+# File I/O
+
+INCLUDE_CFA = defPrimWord("INCLUDE", () -> begin
+ pushPS(32)
+ callPrim(mem[WORD_CFA])
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
+
+ fname = word
+ if !isfile(fname)
+ fname = Pkg.dir("forth","src",word)
+ if !isfile(fname)
+ error("No file named $word found in current directory or package source directory.")
+ end
+ end
+ push!(sources, open(fname, "r"))
+
+ # Clear input buffer
+ mem[NUMTIB] = 0
+
+ return NEXT
+end)
+
+
+#### VM loop ####
+
+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
+
+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_CFA + 1
+
+ # Primitive processing loop.
+ # Everyting else is simply a consequence of this loop!
+ jmp = NEXT
+ while jmp != 0
+ try
+ #println("Entering prim $(getPrimName(jmp))")
+ jmp = callPrim(jmp)
+
+ catch ex
+ showerror(STDOUT, ex)
+ println()
+
+ while !isempty(sources) && currentSource() != STDIN
+ close(pop!(sources))
+ end
+
+ # QUIT
+ reg.IP = ABORT_CFA + 1
+ jmp = NEXT
+ end
+ end
+end
+
+# Debugging tools
+
+TRACE_CFA = defPrimWord("TRACE", () -> begin
+ println("reg.W: $(reg.W) reg.IP: $(reg.IP)")
+ print("PS: "); printPS()
+ print("RS: "); printRS()
+ print("[paused]")
+ readline()
+
+ return NEXT
+end)
+
+function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
+ chars = Array{Char,1}(cellsPerLine)
+
+ lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
+ endAddr = startAddr + count - 1
+
+ q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
+ numLines = q + (r > 0 ? 1 : 0)
+
+ i = lineStartAddr
+ for l in 1:numLines
+ print(i,":")
+
+ for c in 1:cellsPerLine
+ if i >= startAddr && i <= endAddr
+ print("\t",mem[i])
+ if mem[i]>=32 && mem[i]<128
+ chars[c] = Char(mem[i])
+ else
+ chars[c] = '.'
+ end
+ else
+ print("\t")
+ chars[c] = ' '
+ end
+
+ i += 1
+ end
+
+ println("\t", ASCIIString(chars))
+ end
+end
+
+function printPS()
+ count = reg.PSP - PSP0
+
+ if count > 0
+ print("<$count>")
+ for i in (PSP0+1):reg.PSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Parameter stack empty")
+ end
+end
+
+function printRS()
+ count = reg.RSP - RSP0
+
+ if count > 0
+ print("<$count>")
+ for i in (RSP0+1):reg.RSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Return stack empty")
+ end
+end
+
+DUMP = defPrimWord("DUMP", () -> begin
+ count = popPS()
+ addr = popPS()
+
+ println()
+ dump(addr, count=count)
+
+ return NEXT
+end)
+