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author | Den Shabalin <den.shabalin@gmail.com> | 2013-08-08 18:52:33 +0200 |
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committer | Den Shabalin <den.shabalin@gmail.com> | 2013-08-14 11:45:47 +0200 |
commit | a06a771dea3ade03c85fb3835632a8bc54392d5e (patch) | |
tree | 6fb68ad62baac31e0103398c2fc6703d918f7abc /src/compiler | |
parent | 5439c4c9aa9ef03c061fa9c2c4689a722729b8f9 (diff) | |
download | scala-a06a771dea3ade03c85fb3835632a8bc54392d5e.tar.gz scala-a06a771dea3ade03c85fb3835632a8bc54392d5e.tar.bz2 scala-a06a771dea3ade03c85fb3835632a8bc54392d5e.zip |
refactor parser entry points and extract a few methods out
This commit contains three logical changes:
1. Split `templateStatSeq` into two methods as we need more reliable
parsing of template body alone for new `parseStats` entry point.
2. Add new parser entry point called `parseStats` which is aimed towards
use in tools that require parsing of Scala code that can be written
inside of a template.
Such functionality is required for parsing lines in repl, parsing
code through toolbox, parsing and running scala scripts and lastly
for quasiquotes. All of them are refactored to use this very method
in the next commits.
A new method called `templateStatsCompat` is also added to make this
commit pass the tests but it's a temporary hack that will be removed
in next commit in favor of `parseStats`.
3. Extract out a few methods like `isCaseDefStart`, `expectedMsgTemplate`
and `parseRule`. These are needed to override parser behaviour in
updated quasiquotes parser (see next commits).
Diffstat (limited to 'src/compiler')
-rw-r--r-- | src/compiler/scala/tools/nsc/ast/parser/Parsers.scala | 76 |
1 files changed, 46 insertions, 30 deletions
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala index d0b0c09d59..6a10f2dd10 100644 --- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala +++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala @@ -334,22 +334,27 @@ self => def parseStartRule: () => Tree - /** This is the general parse entry point. - */ - def parse(): Tree = { - val t = parseStartRule() + def parseRule[T](rule: this.type => T): T = { + val t = rule(this) accept(EOF) t } + /** This is the general parse entry point. + */ + def parse(): Tree = parseRule(_.parseStartRule()) + + /** This is alternative entry point for repl, script runner, toolbox and quasiquotes. + */ + def parseStats(): List[Tree] = parseRule(_.templateStats()) + /** This is the parse entry point for code which is not self-contained, e.g. * a script which is a series of template statements. They will be * swaddled in Trees until the AST is equivalent to the one returned * by compilationUnit(). */ def scriptBody(): Tree = { - val stmts = templateStats() - accept(EOF) + val stmts = parseStats() def mainModuleName = newTermName(settings.script.value) /* If there is only a single object template in the file and it has a @@ -563,8 +568,8 @@ self => and } - def expectedMsg(token: Int): String = - token2string(token) + " expected but " +token2string(in.token) + " found." + def expectedMsgTemplate(exp: String, fnd: String) = s"$exp expected but $fnd found." + def expectedMsg(token: Int): String = expectedMsgTemplate(token2string(token), token2string(in.token)) /** Consume one token of the specified type, or signal an error if it is not there. */ def accept(token: Int): Int = { @@ -627,6 +632,8 @@ self => def isAnnotation: Boolean = in.token == AT + def isCaseDefStart: Boolean = in.token == CASE + def isLocalModifier: Boolean = in.token match { case ABSTRACT | FINAL | SEALED | IMPLICIT | LAZY => true case _ => false @@ -1298,7 +1305,7 @@ self => in.nextToken() if (in.token != LBRACE) catchFromExpr() else inBracesOrNil { - if (in.token == CASE) caseClauses() + if (isCaseDefStart) caseClauses() else catchFromExpr() } } @@ -1613,7 +1620,7 @@ self => */ def blockExpr(): Tree = atPos(in.offset) { inBraces { - if (in.token == CASE) Match(EmptyTree, caseClauses()) + if (isCaseDefStart) Match(EmptyTree, caseClauses()) else block() } } @@ -2605,7 +2612,7 @@ self => case EQUALS => in.nextToken() TypeDef(mods, name, tparams, typ()) - case SUPERTYPE | SUBTYPE | SEMI | NEWLINE | NEWLINES | COMMA | RBRACE => + case t if t == SUPERTYPE || t == SUBTYPE || t == COMMA || t == RBRACE || isStatSep(t) => TypeDef(mods | Flags.DEFERRED, name, tparams, typeBounds()) case _ => syntaxErrorOrIncompleteAnd("`=', `>:', or `<:' expected", skipIt = true)(EmptyTree) @@ -2906,27 +2913,14 @@ self => stats.toList } - /** Informal - for the repl and other direct parser accessors. - */ - def templateStats(): List[Tree] = templateStatSeq(isPre = false)._2 match { - case Nil => EmptyTree.asList - case stats => stats - } - /** {{{ - * TemplateStatSeq ::= [id [`:' Type] `=>'] TemplateStat {semi TemplateStat} - * TemplateStat ::= Import - * | Annotations Modifiers Def - * | Annotations Modifiers Dcl - * | Expr1 - * | super ArgumentExprs {ArgumentExprs} - * | + * TemplateStatSeq ::= [id [`:' Type] `=>'] TemplateStats * }}} * @param isPre specifies whether in early initializer (true) or not (false) */ def templateStatSeq(isPre : Boolean): (ValDef, List[Tree]) = checkNoEscapingPlaceholders { var self: ValDef = emptyValDef - val stats = new ListBuffer[Tree] + var firstOpt: Option[Tree] = None if (isExprIntro) { in.flushDoc val first = expr(InTemplate) // @S: first statement is potentially converted so cannot be stubbed. @@ -2943,10 +2937,25 @@ self => } in.nextToken() } else { - stats += first + firstOpt = Some(first) acceptStatSepOpt() } } + (self, firstOpt ++: templateStats()) + } + + /** {{{ + * TemplateStats ::= TemplateStat {semi TemplateStat} + * TemplateStat ::= Import + * | Annotations Modifiers Def + * | Annotations Modifiers Dcl + * | Expr1 + * | super ArgumentExprs {ArgumentExprs} + * | + * }}} + */ + def templateStats(): List[Tree] = { + val stats = new ListBuffer[Tree] while (!isStatSeqEnd) { if (in.token == IMPORT) { in.flushDoc @@ -2961,7 +2970,14 @@ self => } acceptStatSepOpt() } - (self, stats.toList) + stats.toList + } + + /** Informal - for the repl and other direct parser accessors. + */ + def templateStatsCompat(): List[Tree] = templateStats() match { + case Nil => EmptyTree.asList + case stats => stats } /** {{{ @@ -3026,14 +3042,14 @@ self => */ def blockStatSeq(): List[Tree] = checkNoEscapingPlaceholders { val stats = new ListBuffer[Tree] - while (!isStatSeqEnd && in.token != CASE) { + while (!isStatSeqEnd && !isCaseDefStart) { if (in.token == IMPORT) { stats ++= importClause() acceptStatSep() } else if (isExprIntro) { stats += statement(InBlock) - if (in.token != RBRACE && in.token != CASE) acceptStatSep() + if (in.token != RBRACE && !isCaseDefStart) acceptStatSep() } else if (isDefIntro || isLocalModifier || isAnnotation) { if (in.token == IMPLICIT) { |