github.com/shogo82148/std@v1.22.1-0.20240327122250-4e474527810c/cmd/compile/internal/syntax/syntax.go (about)

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package syntax
     6  
     7  import (
     8  	"github.com/shogo82148/std/io"
     9  )
    10  
    11  // Mode describes the parser mode.
    12  type Mode uint
    13  
    14  // Modes supported by the parser.
    15  const (
    16  	CheckBranches Mode = 1 << iota
    17  )
    18  
    19  // Error describes a syntax error. Error implements the error interface.
    20  type Error struct {
    21  	Pos Pos
    22  	Msg string
    23  }
    24  
    25  func (err Error) Error() string
    26  
    27  var _ error = Error{}
    28  
    29  // An ErrorHandler is called for each error encountered reading a .go file.
    30  type ErrorHandler func(err error)
    31  
    32  // A Pragma value augments a package, import, const, func, type, or var declaration.
    33  // Its meaning is entirely up to the PragmaHandler,
    34  // except that nil is used to mean “no pragma seen.”
    35  type Pragma interface{}
    36  
    37  // A PragmaHandler is used to process //go: directives while scanning.
    38  // It is passed the current pragma value, which starts out being nil,
    39  // and it returns an updated pragma value.
    40  // The text is the directive, with the "//" prefix stripped.
    41  // The current pragma is saved at each package, import, const, func, type, or var
    42  // declaration, into the File, ImportDecl, ConstDecl, FuncDecl, TypeDecl, or VarDecl node.
    43  //
    44  // If text is the empty string, the pragma is being returned
    45  // to the handler unused, meaning it appeared before a non-declaration.
    46  // The handler may wish to report an error. In this case, pos is the
    47  // current parser position, not the position of the pragma itself.
    48  // Blank specifies whether the line is blank before the pragma.
    49  type PragmaHandler func(pos Pos, blank bool, text string, current Pragma) Pragma
    50  
    51  // Parse parses a single Go source file from src and returns the corresponding
    52  // syntax tree. If there are errors, Parse will return the first error found,
    53  // and a possibly partially constructed syntax tree, or nil.
    54  //
    55  // If errh != nil, it is called with each error encountered, and Parse will
    56  // process as much source as possible. In this case, the returned syntax tree
    57  // is only nil if no correct package clause was found.
    58  // If errh is nil, Parse will terminate immediately upon encountering the first
    59  // error, and the returned syntax tree is nil.
    60  //
    61  // If pragh != nil, it is called with each pragma encountered.
    62  func Parse(base *PosBase, src io.Reader, errh ErrorHandler, pragh PragmaHandler, mode Mode) (_ *File, first error)
    63  
    64  // ParseFile behaves like Parse but it reads the source from the named file.
    65  func ParseFile(filename string, errh ErrorHandler, pragh PragmaHandler, mode Mode) (*File, error)