+ if slashIdx > 0
+ return join(chars[slashIdx:length(chars)])
+ else
+ return nothing
+ end
+ end
+
+ function backspaceStr(s, bsCount)
+ oldLen = length(s)
+ newLen = max(0, oldLen - bsCount)
+ return join(collect(s)[1:newLen])
+ end
+
+ line = ""
+ while true
+ key = Char(getKey())
+
+ if key == '\n'
+ print(" ")
+ return AbstractString(line)
+
+ elseif key == '\x04'
+ if isempty(line)
+ return string("\x04")
+ end
+
+ elseif key == '\b'
+ if !isempty(line)
+ print("\b\033[K")
+ line = backspaceStr(line, 1)
+ end
+
+ elseif key == '\e'
+ # Strip ANSI escape sequence
+ nextKey = Char(getKey())
+ if nextKey == '['
+ while true
+ nextKey = Char(getKey())
+ if nextKey >= '@' || nextKey <= '~'
+ break
+ end
+ end
+ end
+
+ elseif key == '\t'
+ # Currently do nothing
+
+ frag = getFrag(line)
+ if frag != nothing
+ if haskey(REPLCompletions.latex_symbols, frag)
+ print(repeat("\b", length(frag)))
+ print("\033[K")
+ comp = REPLCompletions.latex_symbols[frag]
+ line = string(backspaceStr(line, length(frag)), comp)
+ print(comp)
+ end
+ end
+
+ else
+ print(key)
+ line = string(line, key)
+ end
+ end
+end
+
+SPAN, SPAN_CFA = defNewVar("SPAN", 0)
+EXPECT_CFA = defPrimWord("EXPECT", () -> begin
+ maxLen = popPS()
+ addr = popPS()
+
+ line = getLineFromSTDIN()
+
+ mem[SPAN] = min(length(line), maxLen)
+ putString(line, addr, maxLen)
+
+ 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
+
+FROMLINK_CFA = defPrimWord("LINK>", () -> begin
+
+ addr = popPS()
+ lenAndFlags = mem[addr+1]
+ len = lenAndFlags & F_LENMASK
+
+ pushPS(addr + 2 + len)
+
+ return NEXT
+end)
+
+NUMCONTEXT, NUMCONTEXT_CFA = defNewVar("#CONTEXT", 1)
+
+createHeader("FORTH", 0)
+FORTH_CFA = mem[H]
+dictWrite(defPrim(() -> begin
+ mem[CONTEXT + mem[NUMCONTEXT] - 1] = reg.W
+ return NEXT
+end, name="FORTH"))
+dictWrite(0) # cell for latest
+
+CURRENT_CFA = defExistingVar("CURRENT", CURRENT)
+
+# Switch to new FORTH vocabulary cfa
+mem[FORTH_CFA+1] = mem[mem[CURRENT]+1]
+mem[CURRENT] = FORTH_CFA
+
+CONTEXT, CONTEXT_CFA = defNewVar("CONTEXT", zeros(Int64, 10))
+mem[CONTEXT] = FORTH_CFA
+
+FINDVOCAB_CFA = defPrimWord("FINDVOCAB", () -> begin
+ vocabCFA = popPS()
+ countedAddr = popPS()
+
+ wordAddr = countedAddr + 1
+ wordLen = mem[countedAddr]
+ word = lowercase(getString(wordAddr, wordLen))
+
+ lfa = vocabCFA+1
+ lenAndFlags = 0
+
+ while (lfa = mem[lfa]) > 0
+
+ lenAndFlags = mem[lfa+1]
+ len = lenAndFlags & F_LENMASK
+ hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
+
+ if hidden || len != wordLen
+ continue
+ end
+
+ thisWord = lowercase(getString(lfa+2, len))
+
+ if thisWord == word
+ break
+ end
+ end
+
+ if lfa > 0
+ pushPS(lfa)
+ callPrim(mem[FROMLINK_CFA])
+ if (lenAndFlags & F_IMMED) == F_IMMED
+ pushPS(1)
+ else
+ pushPS(-1)
+ end
+ else
+ pushPS(countedAddr)
+ pushPS(0)
+ end
+
+ return NEXT
+end)
+
+FIND_CFA = defPrimWord("FIND", () -> begin
+
+ countedAddr = popPS()
+ context = mem[CONTEXT:(CONTEXT+mem[NUMCONTEXT]-1)]
+
+ for vocabCFA in reverse(context)
+ pushPS(countedAddr)
+ pushPS(vocabCFA)
+ callPrim(mem[FINDVOCAB_CFA])
+
+ callPrim(mem[DUP_CFA])
+ if popPS() != 0
+ return NEXT
+ else
+ popPS()
+ popPS()
+ end
+ end
+
+ pushPS(countedAddr)
+ pushPS(0)
+
+ 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)
+
+FIB_CFA = defConst("FIB", FIB)
+NUMFIB, NUMFIB_CFA = defNewVar("#FIB", 0)
+
+IB_CFA = defPrimWord("IB", () -> begin
+ pushPS(mem[SOURCE_ID_VAR] == 0 ? TIB : FIB)
+ return NEXT
+end)
+
+NUMIB_CFA = defPrimWord("#IB", () -> begin
+ pushPS(mem[SOURCE_ID_VAR] == 0 ? NUMTIB : NUMFIB)
+ return NEXT
+end)
+
+TOIN, TOIN_CFA = defNewVar(">IN", 0)
+
+SOURCE_ID_VAR, SOURCE_ID_VAR_CFA = defNewVar("SOURCE-ID-VAR", 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])
+
+EOF_FLAG, EOF_FLAG_CFA = defNewVar("EOF-FLAG", 0)
+
+# ( fid -- )
+# EOF-FLAG set to true if EOF is reached
+QUERY_FILE_CFA = defWord("QUERY-FILE",
+ [FIB_CFA, LIT_CFA, 160, ROT_CFA, READ_LINE_CFA,
+ DROP_CFA, EOF_FLAG_CFA, STORE_CFA,
+ NUMFIB_CFA, STORE_CFA,
+ LIT_CFA, 0, TOIN_CFA, STORE_CFA,
+ EXIT_CFA])
+
+WORD_CFA = defPrimWord("WORD", () -> begin
+ delim = popPS()
+
+ if mem[SOURCE_ID_VAR] == 0
+ bufferAddr = TIB
+ sizeAddr = NUMTIB
+ else
+ bufferAddr = FIB
+ sizeAddr = NUMFIB
+ end
+
+ # Chew up initial occurrences of delim
+ while (mem[TOIN]<mem[sizeAddr] && mem[bufferAddr+mem[TOIN]] == delim)
+ mem[TOIN] += 1
+ end
+
+ countAddr = mem[H]
+ addr = mem[H]+1
+
+ # Start reading in word
+ count = 0
+ while (mem[TOIN]<mem[sizeAddr])
+ mem[addr] = mem[bufferAddr+mem[TOIN]]
+ mem[TOIN] += 1
+
+ if (mem[addr] == delim)
+ break
+ end
+
+ count += 1
+ addr += 1
+ end
+
+ # Record count
+ mem[countAddr] = count
+ pushPS(countAddr)
+
+ #println("Processing word: '$(getString(countAddr+1,mem[countAddr]))' (state $(mem[STATE]))")
+
+ return NEXT
+end)
+
+# Compilation
+
+STATE, STATE_CFA = defNewVar("STATE", 0)
+
+COMMA_CFA = defPrimWord(",", () -> begin
+ mem[mem[H]] = popPS()
+ mem[H] += 1
+
+ return NEXT
+end)
+
+HERE_CFA = defWord("HERE",
+ [H_CFA, FETCH_CFA, EXIT_CFA])
+
+HEADER_CFA = defPrimWord("HEADER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
+
+ createHeader(word, 0)
+
+ return NEXT
+end)
+
+CREATE_CFA = defWord("CREATE",
+ [LIT_CFA, 32, WORD_CFA, HEADER_CFA,
+ LIT_CFA, DOVAR, COMMA_CFA,
+ EXIT_CFA])
+
+DODOES = defPrim(() -> begin
+ pushRS(reg.IP)
+ reg.IP = popPS()
+ pushPS(reg.W + 1)
+ return NEXT
+end, name="DODOES")
+
+DOES_HELPER_CFA = defPrimWord("(DOES>)", () -> begin
+
+ pushPS(mem[mem[CURRENT]+1])
+ callPrim(mem[FROMLINK_CFA])
+ cfa = popPS()
+
+ runtimeAddr = popPS()
+
+ mem[cfa] = defPrim(eval(:(() -> begin
+ pushPS($(runtimeAddr))
+ return DODOES
+ end)), name="doesPrim")
+
+ return NEXT
+end, flags=F_IMMED | F_HIDDEN)
+
+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[mem[CURRENT]+1] + 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[mem[CURRENT]+1] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
+ return NEXT
+end, flags=F_IMMED)
+
+# ( addr n -- primAddr )
+CREATE_PRIM_CFA = defPrimWord("CREATE-PRIM", () -> begin
+ len = popPS()
+ addr = popPS()
+
+ exprString = string("() -> begin\n",
+ getString(addr, len), "\n",
+ "return NEXT\n",
+ "end")
+ func = eval(parse(exprString))
+
+ pushPS(defPrim(func))
+ return NEXT
+end)
+
+# 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 input buffer 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
+ print(" ok")
+ end
+ println()
+
+ return NEXT
+end)
+
+QUIT_CFA = defWord("QUIT",
+ [LIT_CFA, 0, STATE_CFA, STORE_CFA, # Set mode to interpret
+ LIT_CFA, 0, SOURCE_ID_VAR_CFA, STORE_CFA, # Set terminal as input stream
+ LIT_CFA, 0, NUMTIB_CFA, STORE_CFA, # Clear the input buffer
+ RSP0_CFA, RSPSTORE_CFA, # Clear the return stack
+ QUERY_CFA, # Read line of input
+ INTERPRET_CFA, PROMPT_CFA, # Interpret line
+ BRANCH_CFA,-4]) # Loop
+
+INCLUDED_CFA = defWord("INCLUDED",
+ [LIT_CFA, 0, STATE_CFA, STORE_CFA, # Set mode to interpret
+ FAM_RO_CFA, OPEN_FILE_CFA, DROP_CFA, # Open the file
+ SOURCE_ID_VAR_CFA, FETCH_CFA, SWAP_CFA, # Store current source on stack
+ SOURCE_ID_VAR_CFA, STORE_CFA, # Mark this as the current source
+ SOURCE_ID_VAR_CFA, FETCH_CFA, QUERY_FILE_CFA, # Read line from file
+ EOF_FLAG_CFA, FETCH_CFA,
+ NUMFIB_CFA, FETCH_CFA, ZE_CFA, AND_CFA, # Test for EOF and empty line
+ INVERT_CFA, ZBRANCH_CFA, 4, # Break out if EOF
+ INTERPRET_CFA, # Interpret line
+ BRANCH_CFA, -14, # Loop
+ SOURCE_ID_VAR_CFA, FETCH_CFA,
+ CLOSE_FILE_CFA, DROP_CFA, # Close file
+ SOURCE_ID_VAR_CFA, STORE_CFA, # Restore input source
+ LIT_CFA, 0, NUMIB_CFA, STORE_CFA, # Zero #IB
+ LIT_CFA, 0, TOIN_CFA, STORE_CFA, # Zero >IN
+ EXIT_CFA])
+
+INCLUDE_CFA = defWord("INCLUDE", [LIT_CFA, 32, WORD_CFA,
+ DUP_CFA, INCR_CFA,
+ SWAP_CFA, FETCH_CFA,
+ INCLUDED_CFA, EXIT_CFA]);
+
+ABORT_CFA = defWord("ABORT",
+ [CLOSE_FILES_CFA, DROP_CFA, PSP0_CFA, PSPSTORE_CFA, QUIT_CFA])
+
+BYE_CFA = defPrimWord("BYE", () -> begin
+ println("\nBye!")
+ return 0
+end)
+
+EOF_CFA = defPrimWord("\x04", () -> begin
+ return 0
+end)
+
+### Library loading ###
+
+oldCWD = ""
+SETLIBCWD_CFA = defPrimWord("SETLIBCWD", () -> begin
+ global oldCWD = pwd()
+ if !isfile("lib.4th") # Exception for debugging.
+ cd(Pkg.dir("forth","src"))
+ end
+ return NEXT
+end)
+
+RESTORECWD_CFA = defPrimWord("RESTORECWD", () -> begin
+ cd(oldCWD)
+ return NEXT
+end)
+
+INCLUDED_LIB_CFA = defWord("INCLUDED-LIB",
+ [SETLIBCWD_CFA, INCLUDED_CFA, RESTORECWD_CFA, EXIT_CFA])
+
+INCLUDE_LIB_CFA = defWord("INCLUDE-LIB", [LIT_CFA, 32, WORD_CFA,
+ DUP_CFA, INCR_CFA,
+ SWAP_CFA, FETCH_CFA,
+ INCLUDED_LIB_CFA, EXIT_CFA]);
+
+SKIP_WELCOME, SKIP_WELCOME_CFA = defNewVar("SKIP-WELCOME", 0)
+
+#### VM loop ####
+
+initialized = false
+libFileName = "lib.4th"
+
+function run(fileName=nothing; initialize=true)
+
+ # Start with IP pointing to first instruction of outer interpreter
+ pushRS(QUIT_CFA+1)
+
+ # Include optional file
+ if fileName != nothing
+ putString(fileName, mem[H])
+ pushPS(mem[H])
+ mem[H] += length(fileName)
+ pushPS(length(fileName))
+ pushRS(INCLUDED_CFA+1)
+
+ mem[SKIP_WELCOME] = -1
+ end
+
+ # Load library files
+ global initialized, libFileName
+ if !initialized && initialize
+ if libFileName != nothing
+ #print("Including definitions from $libFileName...")
+
+ putString(libFileName, mem[H])
+ pushPS(mem[H])
+ pushPS(length(libFileName))
+ pushRS(INCLUDED_LIB_CFA+1)
+
+ initialized = true
+ else
+ println("No library file found. Only primitive words available.")
+ end
+ end
+
+
+ # Primitive processing loop.
+ # Everyting else is simply a consequence of this loop!
+ jmp = mem[EXIT_CFA]
+ while jmp != 0
+ try
+ #print("Entering prim $(getPrimName(jmp)), PS: ")
+ #printPS()
+
+ jmp = callPrim(jmp)
+
+ catch ex
+ showerror(STDOUT, ex)
+ println()
+
+ # 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", AbstractString(chars))