core/interpreter.nim
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 |
import streams, strutils, tables import parser, ../vendor/linenoise type TMinInterpreter* = object stack*: TMinStack parser*: TMinParser currSym: TMinValue filename*: string debugging*: bool evaluating*: bool TMinOperator* = proc (i: var TMinInterpreter) TMinSigil* = proc (i: var TMinInterpreter, sym: string) TMinError* = enum errSystem, errParser, errGeneric, errEmptyStack, errNoQuotation, errUndefined, errIncorrect, errTwoNumbersRequired, errDivisionByZero const ERRORS: array [TMinError, string] = [ "A system error occurred", "A parsing error occurred", "A generic error occurred", "Insufficient items on the stack", "Quotation not found on the stack", "Symbol undefined", "Incorrect items on the stack", "Two numbers are required on the stack", "Division by zero" ] var SYMBOLS* = initOrderedTable[string, TMinOperator]() var SIGILS* = initOrderedTable[string, TMinOperator]() proc newMinInterpreter*(debugging = false): TMinInterpreter = var s:TMinStack = newSeq[TMinValue](0) var p:TMinParser var i:TMinInterpreter = TMinInterpreter(filename: "input", parser: p, stack: s, debugging: debugging, currSym: TMinValue(column: 1, line: 1, kind: minSymbol, symVal: "")) return i proc error*(i: TMinInterpreter, status: TMinError, message = "") = var msg = if message == "": ERRORS[status] else: message if i.filename == "": stderr.writeln("`$1`: Error - $2" %[i.currSym.symVal, msg]) else: stderr.writeln("$1 [$2,$3] `$4`: Error - $5" %[i.filename, $i.currSym.line, $i.currSym.column, i.currSym.symVal, msg]) quit(int(status)) proc open*(i: var TMinInterpreter, stream:PStream, filename: string) = i.filename = filename i.parser.open(stream, filename) proc close*(i: var TMinInterpreter) = i.parser.close(); proc dump*(i: TMinInterpreter): string = var s = "" for item in i.stack: s = s & $item & " " return s proc debug(i: var TMinInterpreter, value: TMinValue) = if i.debugging: stderr.writeln("-- " &i.dump & $value) proc push*(i: var TMinInterpreter, val: TMinValue) = i.debug val if val.kind == minSymbol: if not i.evaluating: i.currSym = val let symbol = val.symVal let sigil = "" & symbol[0] if SYMBOLS.hasKey(val.symVal): try: SYMBOLS[val.symVal](i) except: i.error(errSystem, getCurrentExceptionMsg()) else: if SIGILS.hasKey(sigil) and symbol.len > 1: let sym = symbol[1..symbol.len-1] try: i.stack.add(TMinValue(kind: minString, strVal: sym)) SIGILS[sigil](i) except: i.error(errSystem, getCurrentExceptionMsg()) else: i.error(errUndefined, "Undefined symbol: '"&val.symVal&"'") else: i.stack.add(val) proc push*(i: var TMinInterpreter, q: seq[TMinValue]) = for e in q: i.push e proc pop*(i: var TMinInterpreter): TMinValue = if i.stack.len > 0: return i.stack.pop else: i.error(errEmptyStack) proc peek*(i: TMinInterpreter): TMinValue = if i.stack.len > 0: return i.stack[i.stack.len-1] else: i.error(errEmptyStack) proc interpret*(i: var TMinInterpreter) = var val: TMinValue while i.parser.token != tkEof: try: val = i.parser.parseMinValue except: i.error errParser, getCurrentExceptionMsg() i.push val proc eval*(i: var TMinInterpreter, s: string) = let fn = i.filename try: i.open(newStringStream(s), "eval") discard i.parser.getToken() i.interpret() except: stderr.writeln getCurrentExceptionMsg() finally: i.filename = fn proc load*(i: var TMinInterpreter, s: string) = let fn = i.filename try: i.open(newStringStream(s.readFile), s) discard i.parser.getToken() i.interpret() except: stderr.writeln getCurrentExceptionMsg() finally: i.filename = fn proc apply*(i: var TMinInterpreter, symbol: string) = SYMBOLS[symbol](i) |