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Package printer

import "go/printer"
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Package printer implements printing of AST nodes.

func Fprint

func Fprint(output io.Writer, fset *token.FileSet, node interface{}) error

Fprint "pretty-prints" an AST node to output. It calls Config.Fprint with default settings.

type CommentedNode

type CommentedNode struct {
    Node     interface{} // *ast.File, or ast.Expr, ast.Decl, ast.Spec, or ast.Stmt
    Comments []*ast.CommentGroup
}

A CommentedNode bundles an AST node and corresponding comments. It may be provided as argument to any of the Fprint functions.

type Config

type Config struct {
    Mode     Mode // default: 0
    Tabwidth int  // default: 8
    Indent   int  // default: 0 (all code is indented at least by this much)
}

A Config node controls the output of Fprint.

func (*Config) Fprint

func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{}) error

Fprint "pretty-prints" an AST node to output for a given configuration cfg. Position information is interpreted relative to the file set fset. The node type must be *ast.File, *CommentedNode, []ast.Decl, []ast.Stmt, or assignment-compatible to ast.Expr, ast.Decl, ast.Spec, or ast.Stmt.

type Mode

type Mode uint

A Mode value is a set of flags (or 0). They control printing.

const (
    RawFormat Mode = 1 << iota // do not use a tabwriter; if set, UseSpaces is ignored
    TabIndent                  // use tabs for indentation independent of UseSpaces
    UseSpaces                  // use spaces instead of tabs for alignment
    SourcePos                  // emit //line comments to preserve original source positions
)