core/interpreter.nim
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import streams, strutils, critbits, os import types, parser proc raiseUndefined(msg: string) = raise MinUndefinedError(msg: msg) proc raiseEmptyStack() = raise MinEmptyStackError(msg:"Insufficient items on the stack") proc raiseInvalid(msg: string) = raise MinInvalidError(msg: msg) 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) else: raiseUndefined("Symbol '$1' not found." % key) proc hasSymbol*(scope: ref MinScope, key: string): bool = if scope.symbols.hasKey(key): return true elif scope.parent.isNotNil: return scope.parent.hasSymbol(key) else: return false 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): if scope.symbols[key].sealed: raiseInvalid("Symbol '$1' is sealed." % 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) else: raiseUndefined("Sigil '$1' not found." % key) proc hasSigil*(scope: ref MinScope, key: string): bool = if scope.sigils.hasKey(key): return true elif scope.parent.isNotNil: return scope.parent.hasSigil(key) else: return false proc dump*(i: MinInterpreter): string = var s = "" for item in i.stack: s = s & $item & " " return s proc debug*(i: In, value: MinValue) = if i.debugging: stderr.writeLine("-- " & i.dump & $value) proc debug*(i: In, value: string) = if i.debugging: stderr.writeLine("-- " & value) proc newScope*(i: In, id: string, q: var MinValue) = q.scope = new MinScope q.scope.name = id q.scope.parent = i.scope template createScope*(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 template withScope*(i: In, q: MinValue, body: stmt): stmt {.immediate.} = #i.debug "[scope] " & q.scope.fullname let origScope = i.scope i.scope = q.scope body #i.debug "[scope] " & scope.fullname i.scope = origScope proc copystack*(i: MinInterpreter): MinStack = return i.stack #var s = newSeq[MinValue](0) #for i in i.stack: # s.add i #return s proc newMinInterpreter*(debugging = false): MinInterpreter = var st:MinStack = newSeq[MinValue](0) var pr:MinParser var scope = new MinScope scope.name = "ROOT" var i:MinInterpreter = MinInterpreter( filename: "input", pwd: "", parser: pr, stack: st, scope: scope, debugging: debugging, unsafe: false, currSym: MinValue(column: 1, line: 1, kind: minSymbol, symVal: "") ) return i proc copy*(i: MinInterpreter, filename: string): MinInterpreter = result = newMinInterpreter(debugging = i.debugging) result.filename = filename result.pwd = filename.parentDir result.stack = i.copystack result.scope = i.scope result.currSym = MinValue(column: 1, line: 1, kind: minSymbol, symVal: "") proc error(i: MinInterpreter, message: string) = if i.currSym.filename == "": stderr.writeLine("`$1`: Error - $2" % [i.currSym.symVal, message]) else: stderr.writeLine("$1 [$2,$3] `$4`: Error - $5" % [i.filename, $i.currSym.line, $i.currSym.column, i.currSym.symVal, message]) template execute(i: In, body: stmt) {.immediate.}= let stack = i.copystack try: body except MinRuntimeError: i.stack = stack stderr.writeLine("$1 [$2,$3]: $4" % [i.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()]) except: i.stack = stack i.error(getCurrentExceptionMsg()) proc open*(i: In, stream:Stream, filename: string) = i.filename = filename i.parser.open(stream, filename) proc close*(i: In) = i.parser.close(); proc push*(i: In, val: MinValue) {.gcsafe.} proc execOp*(i: In, op: MinOperator) = case op.kind of minProcOp: op.prc(i) of minValOp: if op.val.kind == minQuotation: for e in op.val.qVal: i.push e else: i.push(op.val) proc push*(i: In, 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 found = i.scope.hasSymbol(symbol) if found: let sym = i.scope.getSymbol(symbol) if i.unsafe: let stack = i.copystack try: i.execOp(sym) except: i.stack = stack raise else: i.execute: i.execOp(sym) else: let found = i.scope.hasSigil(sigil) if symbol.len > 1 and found: let sig = i.scope.getSigil(sigil) let sym = symbol[1..symbol.len-1] i.stack.add(MinValue(kind: minString, strVal: sym)) if i.unsafe: let stack = i.copystack try: i.execOp(sig) except: i.stack = stack raise else: i.execute: i.execOp(sig) else: raiseUndefined("Undefined symbol: '"&val.symVal&"'") else: i.stack.add(val) proc push*(i: In, q: seq[MinValue]) = for e in q: i.push e proc pop*(i: In): MinValue = if i.stack.len > 0: return i.stack.pop else: raiseEmptyStack() proc peek*(i: MinInterpreter): MinValue = if i.stack.len > 0: return i.stack[i.stack.len-1] else: raiseEmptyStack() proc interpret*(i: In) {.gcsafe.}= var val: MinValue while i.parser.token != tkEof: i.execute: val = i.parser.parseMinValue i.push val proc unquote*(i: In, name: string, q: var MinValue) = i.createScope(name, q): for v in q.qVal: i.push v proc eval*(i: In, 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: In, 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: In, symbol: string) = # TODO review i.scope.getSymbol(symbol).prc(i) |