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Diffstat (limited to 'vendor/github.com/src-d/gcfg/doc.go')
| -rw-r--r-- | vendor/github.com/src-d/gcfg/doc.go | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/github.com/src-d/gcfg/doc.go b/vendor/github.com/src-d/gcfg/doc.go new file mode 100644 index 0000000000..2edcb41a08 --- /dev/null +++ b/vendor/github.com/src-d/gcfg/doc.go @@ -0,0 +1,145 @@ +// Package gcfg reads "INI-style" text-based configuration files with +// "name=value" pairs grouped into sections (gcfg files). +// +// This package is still a work in progress; see the sections below for planned +// changes. +// +// Syntax +// +// The syntax is based on that used by git config: +// http://git-scm.com/docs/git-config#_syntax . +// There are some (planned) differences compared to the git config format: +// - improve data portability: +// - must be encoded in UTF-8 (for now) and must not contain the 0 byte +// - include and "path" type is not supported +// (path type may be implementable as a user-defined type) +// - internationalization +// - section and variable names can contain unicode letters, unicode digits +// (as defined in http://golang.org/ref/spec#Characters ) and hyphens +// (U+002D), starting with a unicode letter +// - disallow potentially ambiguous or misleading definitions: +// - `[sec.sub]` format is not allowed (deprecated in gitconfig) +// - `[sec ""]` is not allowed +// - use `[sec]` for section name "sec" and empty subsection name +// - (planned) within a single file, definitions must be contiguous for each: +// - section: '[secA]' -> '[secB]' -> '[secA]' is an error +// - subsection: '[sec "A"]' -> '[sec "B"]' -> '[sec "A"]' is an error +// - multivalued variable: 'multi=a' -> 'other=x' -> 'multi=b' is an error +// +// Data structure +// +// The functions in this package read values into a user-defined struct. +// Each section corresponds to a struct field in the config struct, and each +// variable in a section corresponds to a data field in the section struct. +// The mapping of each section or variable name to fields is done either based +// on the "gcfg" struct tag or by matching the name of the section or variable, +// ignoring case. In the latter case, hyphens '-' in section and variable names +// correspond to underscores '_' in field names. +// Fields must be exported; to use a section or variable name starting with a +// letter that is neither upper- or lower-case, prefix the field name with 'X'. +// (See https://code.google.com/p/go/issues/detail?id=5763#c4 .) +// +// For sections with subsections, the corresponding field in config must be a +// map, rather than a struct, with string keys and pointer-to-struct values. +// Values for subsection variables are stored in the map with the subsection +// name used as the map key. +// (Note that unlike section and variable names, subsection names are case +// sensitive.) +// When using a map, and there is a section with the same section name but +// without a subsection name, its values are stored with the empty string used +// as the key. +// It is possible to provide default values for subsections in the section +// "default-<sectionname>" (or by setting values in the corresponding struct +// field "Default_<sectionname>"). +// +// The functions in this package panic if config is not a pointer to a struct, +// or when a field is not of a suitable type (either a struct or a map with +// string keys and pointer-to-struct values). +// +// Parsing of values +// +// The section structs in the config struct may contain single-valued or +// multi-valued variables. Variables of unnamed slice type (that is, a type +// starting with `[]`) are treated as multi-value; all others (including named +// slice types) are treated as single-valued variables. +// +// Single-valued variables are handled based on the type as follows. +// Unnamed pointer types (that is, types starting with `*`) are dereferenced, +// and if necessary, a new instance is allocated. +// +// For types implementing the encoding.TextUnmarshaler interface, the +// UnmarshalText method is used to set the value. Implementing this method is +// the recommended way for parsing user-defined types. +// +// For fields of string kind, the value string is assigned to the field, after +// unquoting and unescaping as needed. +// For fields of bool kind, the field is set to true if the value is "true", +// "yes", "on" or "1", and set to false if the value is "false", "no", "off" or +// "0", ignoring case. In addition, single-valued bool fields can be specified +// with a "blank" value (variable name without equals sign and value); in such +// case the value is set to true. +// +// Predefined integer types [u]int(|8|16|32|64) and big.Int are parsed as +// decimal or hexadecimal (if having '0x' prefix). (This is to prevent +// unintuitively handling zero-padded numbers as octal.) Other types having +// [u]int* as the underlying type, such as os.FileMode and uintptr allow +// decimal, hexadecimal, or octal values. +// Parsing mode for integer types can be overridden using the struct tag option +// ",int=mode" where mode is a combination of the 'd', 'h', and 'o' characters +// (each standing for decimal, hexadecimal, and octal, respectively.) +// +// All other types are parsed using fmt.Sscanf with the "%v" verb. +// +// For multi-valued variables, each individual value is parsed as above and +// appended to the slice. If the first value is specified as a "blank" value +// (variable name without equals sign and value), a new slice is allocated; +// that is any values previously set in the slice will be ignored. +// +// The types subpackage for provides helpers for parsing "enum-like" and integer +// types. +// +// Error handling +// +// There are 3 types of errors: +// +// - programmer errors / panics: +// - invalid configuration structure +// - data errors: +// - fatal errors: +// - invalid configuration syntax +// - warnings: +// - data that doesn't belong to any part of the config structure +// +// Programmer errors trigger panics. These are should be fixed by the programmer +// before releasing code that uses gcfg. +// +// Data errors cause gcfg to return a non-nil error value. This includes the +// case when there are extra unknown key-value definitions in the configuration +// data (extra data). +// However, in some occasions it is desirable to be able to proceed in +// situations when the only data error is that of extra data. +// These errors are handled at a different (warning) priority and can be +// filtered out programmatically. To ignore extra data warnings, wrap the +// gcfg.Read*Into invocation into a call to gcfg.FatalOnly. +// +// TODO +// +// The following is a list of changes under consideration: +// - documentation +// - self-contained syntax documentation +// - more practical examples +// - move TODOs to issue tracker (eventually) +// - syntax +// - reconsider valid escape sequences +// (gitconfig doesn't support \r in value, \t in subsection name, etc.) +// - reading / parsing gcfg files +// - define internal representation structure +// - support multiple inputs (readers, strings, files) +// - support declaring encoding (?) +// - support varying fields sets for subsections (?) +// - writing gcfg files +// - error handling +// - make error context accessible programmatically? +// - limit input size? +// +package gcfg // import "github.com/src-d/gcfg" |