#
#
# 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 noidentError(n, origin: PNode) =
var m = ""
if origin != nil:
m.add "in expression '" & origin.renderTree & "': "
m.add "identifier expected, but found '" & n.renderTree & "'"
localError(n.info, m)
proc considerQuotedIdent*(n: PNode, origin: PNode = nil): PIdent =
## Retrieve a PIdent from a PNode, taking into account accent nodes.
## ``origin`` can be nil. If it is not nil, it is used for a better
## error message.
template handleError(n, origin: PNode) =
noidentError(n, origin)
result = getIdent"<Error>"
case n.kind
of nkIdent: result = n.ident
of nkSym: result = n.sym.name
of nkAccQuoted:
case n.len
of 0: handleError(n, origin)
of 1: result = considerQuotedIdent(n.sons[0], origin)
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: handleError(n, origin)
result = getIdent(id)
of nkOpenSymChoice, nkClosedSymChoice: result = n.sons[0].sym.name
else:
handleError(n, origin)
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):
var ti: TIdentIter
var candidate = initIdentIter(ti, scope.symbols, s)
while candidate != nil:
if candidate.kind in filter: return candidate
candidate = nextIdentIter(ti, scope.symbols)
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(c), 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.compilesContextId == 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, skIterator: 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 and
s.typ.kind != tyGenericParam:
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, info: TLineInfo) =
if not c.currentScope.addUniqueSym(sym):
wrongRedefinition(info, sym.name.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(toLowerAscii(x.s[0]) & x.s.substr(1))
of 'a'..'z': result = getIdent(toLowerAscii(x.s[0]) & x.s.substr(1))
else: result = x
template fixSpelling(n: PNode; ident: PIdent; op: untyped) =
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: untyped) = discard
proc errorUseQualifier*(c: PContext; info: TLineInfo; s: PSym) =
var err = "Error: ambiguous identifier: '" & s.name.s & "'"
var ti: TIdentIter
var candidate = initIdentIter(ti, c.importTable.symbols, s.name)
var i = 0
while candidate != nil:
if i == 0: err.add " --use "
else: err.add " or "
err.add candidate.owner.name.s & "." & candidate.name.s
candidate = nextIdentIter(ti, c.importTable.symbols)
inc i
localError(info, errGenerated, err)
proc errorUndeclaredIdentifier*(c: PContext; info: TLineInfo; name: string) =
var err = "undeclared identifier: '" & name & "'"
if c.recursiveDep.len > 0:
err.add "\nThis might be caused by a recursive module dependency: "
err.add c.recursiveDep
# prevent excessive errors for 'nim check'
c.recursiveDep = nil
localError(info, errGenerated, err)
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)
errorUndeclaredIdentifier(c, n.info, 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)
errorUndeclaredIdentifier(c, n.info, ident.s)
result = errorSym(c, n)
else:
internalError(n.info, "lookUp")
return
if contains(c.ambiguousSymbols, result.id):
errorUseQualifier(c, n.info, result)
if result.kind == skStub: loadStub(result)
type
TLookupFlag* = enum
checkAmbiguity, checkUndeclared, checkModule
proc qualifiedLookUp*(c: PContext, n: PNode, flags: set[TLookupFlag]): PSym =
const allExceptModule = {low(TSymKind)..high(TSymKind)}-{skModule,skPackage}
case n.kind
of nkIdent, nkAccQuoted:
var ident = considerQuotedIdent(n)
if checkModule in flags:
result = searchInScopes(c, ident).skipAlias(n)
else:
result = searchInScopes(c, ident, allExceptModule).skipAlias(n)
if result == nil and checkUndeclared in flags:
fixSpelling(n, ident, searchInScopes)
errorUndeclaredIdentifier(c, n.info, ident.s)
result = errorSym(c, n)
elif checkAmbiguity in flags and result != nil and
contains(c.ambiguousSymbols, result.id):
errorUseQualifier(c, n.info, result)
of nkSym:
result = n.sym
if checkAmbiguity in flags and contains(c.ambiguousSymbols, result.id):
errorUseQualifier(c, n.info, n.sym)
of nkDotExpr:
result = nil
var m = qualifiedLookUp(c, n.sons[0], (flags*{checkUndeclared})+{checkModule})
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)
errorUndeclaredIdentifier(c, n.sons[1].info, 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], {checkUndeclared, checkModule})
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], n)
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:
noidentError(n.sons[1], n)
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)
proc isInfixAs*(n: PNode): bool =
return n.kind == nkInfix and considerQuotedIdent(n[0]).s == "as"