tour - touring some programming systems

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# # # The Nim Compiler # (c) Copyright 2015 Andreas Rumpf # # See the file "copying.txt", included in this # distribution, for details about the copyright. # # This module implements lookup helpers. import intsets, ast, astalgo, idents, semdata, types, msgs, options, rodread, renderer, wordrecg, idgen, nimfix.prettybase proc ensureNoMissingOrUnusedSymbols(scope: PScope) proc considerQuotedIdent*(n: PNode): PIdent = ## Retrieve a PIdent from a PNode, taking into account accent nodes. case n.kind of nkIdent: result = n.ident of nkSym: result = n.sym.name of nkAccQuoted: case n.len of 0: localError(n.info, errIdentifierExpected, renderTree(n)) result = getIdent"<Error>" of 1: result = considerQuotedIdent(n.sons[0]) else: var id = "" for i in 0.. <n.len: let x = n.sons[i] case x.kind of nkIdent: id.add(x.ident.s) of nkSym: id.add(x.sym.name.s) else: localError(n.info, errIdentifierExpected, renderTree(n)) return getIdent"<Error>" result = getIdent(id) of nkOpenSymChoice, nkClosedSymChoice: result = n.sons[0].sym.name else: localError(n.info, errIdentifierExpected, renderTree(n)) result = getIdent"<Error>" template addSym*(scope: PScope, s: PSym) = strTableAdd(scope.symbols, s) proc addUniqueSym*(scope: PScope, s: PSym): bool = result = not strTableIncl(scope.symbols, s) proc openScope*(c: PContext): PScope {.discardable.} = result = PScope(parent: c.currentScope, symbols: newStrTable(), depthLevel: c.scopeDepth + 1) c.currentScope = result proc rawCloseScope*(c: PContext) = c.currentScope = c.currentScope.parent proc closeScope*(c: PContext) = ensureNoMissingOrUnusedSymbols(c.currentScope) rawCloseScope(c) iterator walkScopes*(scope: PScope): PScope = var current = scope while current != nil: yield current current = current.parent proc skipAlias*(s: PSym; n: PNode): PSym = if s == nil or s.kind != skAlias: result = s else: result = s.owner if gCmd == cmdPretty: prettybase.replaceDeprecated(n.info, s, result) else: message(n.info, warnDeprecated, "use " & result.name.s & " instead; " & s.name.s) proc localSearchInScope*(c: PContext, s: PIdent): PSym = result = strTableGet(c.currentScope.symbols, s) proc searchInScopes*(c: PContext, s: PIdent): PSym = for scope in walkScopes(c.currentScope): result = strTableGet(scope.symbols, s) if result != nil: return result = nil proc debugScopes*(c: PContext; limit=0) {.deprecated.} = var i = 0 for scope in walkScopes(c.currentScope): echo "scope ", i for h in 0 .. high(scope.symbols.data): if scope.symbols.data[h] != nil: echo scope.symbols.data[h].name.s if i == limit: break inc i proc searchInScopes*(c: PContext, s: PIdent, filter: TSymKinds): PSym = for scope in walkScopes(c.currentScope): result = strTableGet(scope.symbols, s) if result != nil and result.kind in filter: return result = nil proc errorSym*(c: PContext, n: PNode): PSym = ## creates an error symbol to avoid cascading errors (for IDE support) var m = n # ensure that 'considerQuotedIdent' can't fail: if m.kind == nkDotExpr: m = m.sons[1] let ident = if m.kind in {nkIdent, nkSym, nkAccQuoted}: considerQuotedIdent(m) else: getIdent("err:" & renderTree(m)) result = newSym(skError, ident, getCurrOwner(), n.info) result.typ = errorType(c) incl(result.flags, sfDiscardable) # pretend it's imported from some unknown module to prevent cascading errors: if gCmd != cmdInteractive and c.inCompilesContext == 0: c.importTable.addSym(result) type TOverloadIterMode* = enum oimDone, oimNoQualifier, oimSelfModule, oimOtherModule, oimSymChoice, oimSymChoiceLocalLookup TOverloadIter*{.final.} = object it*: TIdentIter m*: PSym mode*: TOverloadIterMode symChoiceIndex*: int scope*: PScope inSymChoice: IntSet proc getSymRepr*(s: PSym): string = case s.kind of skProc, skMethod, skConverter, skIterators: result = getProcHeader(s) else: result = s.name.s proc ensureNoMissingOrUnusedSymbols(scope: PScope) = # check if all symbols have been used and defined: var it: TTabIter var s = initTabIter(it, scope.symbols) var missingImpls = 0 while s != nil: if sfForward in s.flags: # too many 'implementation of X' errors are annoying # and slow 'suggest' down: if missingImpls == 0: localError(s.info, errImplOfXexpected, getSymRepr(s)) inc missingImpls elif {sfUsed, sfExported} * s.flags == {} and optHints in s.options: # BUGFIX: check options in s! if s.kind notin {skForVar, skParam, skMethod, skUnknown, skGenericParam}: # XXX: implicit type params are currently skTypes # maybe they can be made skGenericParam as well. if s.typ != nil and tfImplicitTypeParam notin s.typ.flags: message(s.info, hintXDeclaredButNotUsed, getSymRepr(s)) s = nextIter(it, scope.symbols) proc wrongRedefinition*(info: TLineInfo, s: string) = if gCmd != cmdInteractive: localError(info, errAttemptToRedefine, s) proc addDecl*(c: PContext, sym: PSym) = if not c.currentScope.addUniqueSym(sym): wrongRedefinition(sym.info, sym.name.s) proc addPrelimDecl*(c: PContext, sym: PSym) = discard c.currentScope.addUniqueSym(sym) proc addDeclAt*(scope: PScope, sym: PSym) = if not scope.addUniqueSym(sym): wrongRedefinition(sym.info, sym.name.s) proc addInterfaceDeclAux(c: PContext, sym: PSym) = if sfExported in sym.flags: # add to interface: if c.module != nil: strTableAdd(c.module.tab, sym) else: internalError(sym.info, "addInterfaceDeclAux") proc addInterfaceDeclAt*(c: PContext, scope: PScope, sym: PSym) = addDeclAt(scope, sym) addInterfaceDeclAux(c, sym) proc addOverloadableSymAt*(scope: PScope, fn: PSym) = if fn.kind notin OverloadableSyms: internalError(fn.info, "addOverloadableSymAt") return let check = strTableGet(scope.symbols, fn.name) if check != nil and check.kind notin OverloadableSyms: wrongRedefinition(fn.info, fn.name.s) else: scope.addSym(fn) proc addInterfaceDecl*(c: PContext, sym: PSym) = # it adds the symbol to the interface if appropriate addDecl(c, sym) addInterfaceDeclAux(c, sym) proc addInterfaceOverloadableSymAt*(c: PContext, scope: PScope, sym: PSym) = # it adds the symbol to the interface if appropriate addOverloadableSymAt(scope, sym) addInterfaceDeclAux(c, sym) when defined(nimfix): import strutils # when we cannot find the identifier, retry with a changed identifer: proc altSpelling(x: PIdent): PIdent = case x.s[0] of 'A'..'Z': result = getIdent(toLower(x.s[0]) & x.s.substr(1)) of 'a'..'z': result = getIdent(toLower(x.s[0]) & x.s.substr(1)) else: result = x template fixSpelling(n: PNode; ident: PIdent; op: expr) = let alt = ident.altSpelling result = op(c, alt).skipAlias(n) if result != nil: prettybase.replaceDeprecated(n.info, ident, alt) return result else: template fixSpelling(n: PNode; ident: PIdent; op: expr) = discard proc lookUp*(c: PContext, n: PNode): PSym = # Looks up a symbol. Generates an error in case of nil. case n.kind of nkIdent: result = searchInScopes(c, n.ident).skipAlias(n) if result == nil: fixSpelling(n, n.ident, searchInScopes) localError(n.info, errUndeclaredIdentifier, n.ident.s) result = errorSym(c, n) of nkSym: result = n.sym of nkAccQuoted: var ident = considerQuotedIdent(n) result = searchInScopes(c, ident).skipAlias(n) if result == nil: fixSpelling(n, ident, searchInScopes) localError(n.info, errUndeclaredIdentifier, ident.s) result = errorSym(c, n) else: internalError(n.info, "lookUp") return if contains(c.ambiguousSymbols, result.id): localError(n.info, errUseQualifier, result.name.s) if result.kind == skStub: loadStub(result) type TLookupFlag* = enum checkAmbiguity, checkUndeclared proc qualifiedLookUp*(c: PContext, n: PNode, flags = {checkUndeclared}): PSym = case n.kind of nkIdent, nkAccQuoted: var ident = considerQuotedIdent(n) result = searchInScopes(c, ident).skipAlias(n) if result == nil and checkUndeclared in flags: fixSpelling(n, ident, searchInScopes) localError(n.info, errUndeclaredIdentifier, ident.s) result = errorSym(c, n) elif checkAmbiguity in flags and result != nil and contains(c.ambiguousSymbols, result.id): localError(n.info, errUseQualifier, ident.s) of nkSym: result = n.sym if checkAmbiguity in flags and contains(c.ambiguousSymbols, result.id): localError(n.info, errUseQualifier, n.sym.name.s) of nkDotExpr: result = nil var m = qualifiedLookUp(c, n.sons[0], flags*{checkUndeclared}) if m != nil and m.kind == skModule: var ident: PIdent = nil if n.sons[1].kind == nkIdent: ident = n.sons[1].ident elif n.sons[1].kind == nkAccQuoted: ident = considerQuotedIdent(n.sons[1]) if ident != nil: if m == c.module: result = strTableGet(c.topLevelScope.symbols, ident).skipAlias(n) else: result = strTableGet(m.tab, ident).skipAlias(n) if result == nil and checkUndeclared in flags: fixSpelling(n.sons[1], ident, searchInScopes) localError(n.sons[1].info, errUndeclaredIdentifier, ident.s) result = errorSym(c, n.sons[1]) elif n.sons[1].kind == nkSym: result = n.sons[1].sym elif checkUndeclared in flags and n.sons[1].kind notin {nkOpenSymChoice, nkClosedSymChoice}: localError(n.sons[1].info, errIdentifierExpected, renderTree(n.sons[1])) result = errorSym(c, n.sons[1]) else: result = nil if result != nil and result.kind == skStub: loadStub(result) proc initOverloadIter*(o: var TOverloadIter, c: PContext, n: PNode): PSym = case n.kind of nkIdent, nkAccQuoted: var ident = considerQuotedIdent(n) o.scope = c.currentScope o.mode = oimNoQualifier while true: result = initIdentIter(o.it, o.scope.symbols, ident).skipAlias(n) if result != nil: break else: o.scope = o.scope.parent if o.scope == nil: break of nkSym: result = n.sym o.mode = oimDone of nkDotExpr: o.mode = oimOtherModule o.m = qualifiedLookUp(c, n.sons[0]) if o.m != nil and o.m.kind == skModule: var ident: PIdent = nil if n.sons[1].kind == nkIdent: ident = n.sons[1].ident elif n.sons[1].kind == nkAccQuoted: ident = considerQuotedIdent(n.sons[1]) if ident != nil: if o.m == c.module: # a module may access its private members: result = initIdentIter(o.it, c.topLevelScope.symbols, ident).skipAlias(n) o.mode = oimSelfModule else: result = initIdentIter(o.it, o.m.tab, ident).skipAlias(n) else: localError(n.sons[1].info, errIdentifierExpected, renderTree(n.sons[1])) result = errorSym(c, n.sons[1]) of nkClosedSymChoice, nkOpenSymChoice: o.mode = oimSymChoice result = n.sons[0].sym o.symChoiceIndex = 1 o.inSymChoice = initIntSet() incl(o.inSymChoice, result.id) else: discard if result != nil and result.kind == skStub: loadStub(result) proc lastOverloadScope*(o: TOverloadIter): int = case o.mode of oimNoQualifier: result = if o.scope.isNil: -1 else: o.scope.depthLevel of oimSelfModule: result = 1 of oimOtherModule: result = 0 else: result = -1 proc nextOverloadIter*(o: var TOverloadIter, c: PContext, n: PNode): PSym = case o.mode of oimDone: result = nil of oimNoQualifier: if o.scope != nil: result = nextIdentIter(o.it, o.scope.symbols).skipAlias(n) while result == nil: o.scope = o.scope.parent if o.scope == nil: break result = initIdentIter(o.it, o.scope.symbols, o.it.name).skipAlias(n) # BUGFIX: o.it.name <-> n.ident else: result = nil of oimSelfModule: result = nextIdentIter(o.it, c.topLevelScope.symbols).skipAlias(n) of oimOtherModule: result = nextIdentIter(o.it, o.m.tab).skipAlias(n) of oimSymChoice: if o.symChoiceIndex < sonsLen(n): result = n.sons[o.symChoiceIndex].sym incl(o.inSymChoice, result.id) inc o.symChoiceIndex elif n.kind == nkOpenSymChoice: # try 'local' symbols too for Koenig's lookup: o.mode = oimSymChoiceLocalLookup o.scope = c.currentScope result = firstIdentExcluding(o.it, o.scope.symbols, n.sons[0].sym.name, o.inSymChoice).skipAlias(n) while result == nil: o.scope = o.scope.parent if o.scope == nil: break result = firstIdentExcluding(o.it, o.scope.symbols, n.sons[0].sym.name, o.inSymChoice).skipAlias(n) of oimSymChoiceLocalLookup: result = nextIdentExcluding(o.it, o.scope.symbols, o.inSymChoice).skipAlias(n) while result == nil: o.scope = o.scope.parent if o.scope == nil: break result = firstIdentExcluding(o.it, o.scope.symbols, n.sons[0].sym.name, o.inSymChoice).skipAlias(n) if result != nil and result.kind == skStub: loadStub(result) proc pickSym*(c: PContext, n: PNode; kind: TSymKind; flags: TSymFlags = {}): PSym = var o: TOverloadIter var a = initOverloadIter(o, c, n) while a != nil: if a.kind == kind and flags <= a.flags: return a a = nextOverloadIter(o, c, n)


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