This module implements the parser of the standard Nimskull syntax. The parser strictly reflects the grammar ("doc/grammar.txt"); however it uses several helper routines to keep the parser small. A special efficient algorithm is used for the precedence levels. The parser here can be seen as a refinement of the grammar, as it specifies how the AST is built from the grammar and how comments belong to the AST.
Types
Parser = object currInd: int ## current indentation level firstTok: bool ## Has the first token been read? hasProgress: bool ## some while loop requires progress ensurance lex*: Lexer ## The lexer that is used for parsing tok*: Token ## The current token lineStartPrevious*: int lineNumberPrevious*: int bufposPrevious*: int inPragma*: int ## Pragma level inSemiStmtList*: int emptyNode: ParsedNode diags*: ParseDiags
- A Parser object represents a file that is being parsed Source Edit
ParserError = object of CatchableError instLoc*: InstantiationInfo
- Source Edit
Procs
proc closeParser(p: var Parser) {....raises: [], tags: [].}
- Close a parser, freeing up its resources. Source Edit
proc openParser(p: var Parser; fileIdx: FileIndex; inputStream: PLLStream; cache: IdentCache; config: ConfigRef) {. ...raises: [IOError, Exception, ValueError, ERecoverableError], tags: [ReadIOEffect, RootEffect].}
- Open a parser, using the given arguments to set up its internal state. Source Edit
proc openParser(p: var Parser; filename: AbsoluteFile; inputStream: PLLStream; cache: IdentCache; config: ConfigRef) {. ...raises: [IOError, Exception, ValueError, ERecoverableError, KeyError], tags: [ReadIOEffect, RootEffect, ReadDirEffect].}
- Source Edit
proc parseAll(p: var Parser): ParsedNode {. ...raises: [IOError, Exception, ValueError, ERecoverableError], tags: [ReadIOEffect, RootEffect].}
- Parses the rest of the input stream held by the parser into a ParsedNode. Source Edit
proc parseString(s: string; cache: IdentCache; config: ConfigRef; filename: string = ""; line: int = 0): ParsedNode {. ...raises: [IOError, Exception, ValueError, ERecoverableError, KeyError], tags: [ReadIOEffect, RootEffect, ReadDirEffect].}
- Parses a string into an AST, returning the top node. filename and line, although optional, provide info so that the compiler can generate correct error messages referring to the original source. Source Edit
proc parseTopLevelStmt(p: var Parser): ParsedNode {. ...raises: [Exception, ERecoverableError, IOError, ValueError], tags: [RootEffect, ReadIOEffect].}
- Implements an iterator which, when called repeatedly, returns the next top-level statement or emptyNode if end of stream. Source Edit