core/interpreter.nim
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import streams, strutils, critbits, os import types, parser, ../vendor/linenoise const ERRORS: array [MinError, 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", "Runtime error", "Two numbers are required on the stack", "Division by zero" ] var ROOT*: ref MinScope = new MinScope ROOT.name = "ROOT" proc fullname*(scope: ref MinScope): string = result = scope.name if scope.parent.isNotNil: result = scope.parent.fullname & ":" & result proc getSymbol*(scope: ref MinScope, key: string): MinOperator = if scope.symbols.hasKey(key): return scope.symbols[key] elif scope.parent.isNotNil: return scope.parent.getSymbol(key) proc delSymbol*(scope: ref MinScope, key: string): bool {.discardable.}= if scope.symbols.hasKey(key): scope.symbols.excl(key) return true return false proc setSymbol*(scope: ref MinScope, key: string, value: MinOperator): bool {.discardable.}= result = false # check if a symbol already exists in current scope if scope.isNotNil and scope.symbols.hasKey(key): scope.symbols[key] = value result = true else: # Go up the scope chain and attempt to find the symbol if scope.parent.isNotNil: result = scope.parent.setSymbol(key, value) proc getSigil*(scope: ref MinScope, key: string): MinOperator = if scope.sigils.hasKey(key): return scope.sigils[key] elif scope.parent.isNotNil: return scope.parent.getSigil(key) proc dump*(i: MinInterpreter): string = var s = "" for item in i.stack: s = s & $item & " " return s proc debug*(i: var MinInterpreter, value: MinValue) = if i.debugging: stderr.writeLine("-- " & i.dump & $value) proc debug*(i: var MinInterpreter, value: string) = if i.debugging: stderr.writeLine("-- " & value) template newScope*(i: In, id: string, q: MinValue, body: stmt): stmt {.immediate.}= q.scope = new MinScope q.scope.name = id q.scope.parent = i.scope #i.debug "[scope] " & q.scope.fullname let scope = i.scope i.scope = q.scope body #i.debug "[scope] " & scope.fullname i.scope = scope proc newMinInterpreter*(debugging = false): MinInterpreter = var st:MinStack = newSeq[MinValue](0) var pr:MinParser var i:MinInterpreter = MinInterpreter( filename: "input", pwd: "", parser: pr, stack: st, scope: ROOT, debugging: debugging, unsafe: false, currSym: MinValue(column: 1, line: 1, kind: minSymbol, symVal: "") ) return i proc copy(i: MinInterpreter, filename = "input"): MinInterpreter = result = newMinInterpreter(debugging = i.debugging) result.filename = filename result.pwd = filename.parentDir result.stack = i.stack result.scope = i.scope result.currSym = MinValue(column: 1, line: 1, kind: minSymbol, symVal: "") proc error*(i: MinInterpreter, status: MinError, message = "") = var msg = if message == "": ERRORS[status] else: message if i.currSym.filename == "": stderr.writeLine("`$1`: Error - $2" % [i.currSym.symVal, msg]) else: stderr.writeLine("$1 [$2,$3] `$4`: Error - $5" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, i.currSym.symVal, msg]) quit(int(status)) proc open*(i: var MinInterpreter, stream:Stream, filename: string) = i.filename = filename i.parser.open(stream, filename) proc close*(i: var MinInterpreter) = i.parser.close(); proc push*(i: var MinInterpreter, val: MinValue) = i.debug val if val.kind == minSymbol: if not i.evaluating: i.currSym = val let symbol = val.symVal let sigil = "" & symbol[0] let symbolProc = i.scope.getSymbol(symbol) if symbolProc.isNotNil: if i.unsafe: symbolProc(i) else: try: symbolProc(i) except MinRuntimeError: stderr.writeLine("$1 [$2,$3]: $4" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()]) except: i.error(errSystem, getCurrentExceptionMsg()) else: let sigilProc = i.scope.getSigil(sigil) if symbol.len > 1 and sigilProc.isNotNil: let sym = symbol[1..symbol.len-1] i.stack.add(MinValue(kind: minString, strVal: sym)) if i.unsafe: sigilProc(i) else: try: sigilProc(i) except MinRuntimeError: stderr.writeLine("$1 [$2,$3]: $4" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()]) except: i.error(errSystem, getCurrentExceptionMsg()) else: i.error(errUndefined, "Undefined symbol: '"&val.symVal&"'") return else: i.stack.add(val) proc push*(i: var MinInterpreter, q: seq[MinValue]) = for e in q: i.push e proc pop*(i: var MinInterpreter): MinValue = if i.stack.len > 0: return i.stack.pop else: i.error(errEmptyStack) proc peek*(i: MinInterpreter): MinValue = if i.stack.len > 0: return i.stack[i.stack.len-1] else: i.error(errEmptyStack) proc interpret*(i: var MinInterpreter) = var val: MinValue while i.parser.token != tkEof: try: val = i.parser.parseMinValue except: i.error errParser, getCurrentExceptionMsg() i.push val proc unquote*(i: In, name: string, q: var MinValue) = i.newScope(name, q): for v in q.qVal: i.push v proc eval*(i: var MinInterpreter, s: string) = let fn = i.filename try: var i2 = i.copy("eval") i2.open(newStringStream(s), "eval") discard i2.parser.getToken() i2.interpret() i.stack = i2.stack i.scope = i2.scope except: stderr.writeLine getCurrentExceptionMsg() finally: i.filename = fn proc load*(i: var MinInterpreter, s: string) = let fn = i.filename try: var i2 = i.copy(s) i2.open(newStringStream(s.readFile), s) discard i2.parser.getToken() i2.interpret() i.stack = i2.stack i.scope = i2.scope except: stderr.writeLine getCurrentExceptionMsg() finally: i.filename = fn proc apply*(i: var MinInterpreter, symbol: string) = i.scope.getSymbol(symbol)(i) proc copystack*(i: var MinInterpreter): MinStack = var s = newSeq[MinValue](0) for i in i.stack: s.add i return s var INTERPRETER* = newMinInterpreter() |