README
¶
pego
This is a pattern matching library for Go. It is based on lpeg, which uses a flavor of PEG.
This is the official continuation of the project of the same name started by Markus Jarderot. He wrote the implementation and I've updated the project to work with newer Go versions.
The original project page is located here: https://code.google.com/p/pego/
##Example
pat := Grm("S", map[string]*Pattern{
"S": Ref("A").Clist(),
"A": Seq(
NegSet("()").Rep(0, -1),
Seq(
Ref("B"),
NegSet("()").Rep(0, -1),
).Rep(0, -1)).Csimple(),
"B": Seq(
"(", Ref("A"), ")"),
})
##More information
- LPeg - Parsing Expression Grammars For Lua - Source of inspiration
- A Text Pattern-Matching Tool based on Parsing Expression Grammars - Paper on the implementation of LPeg.
Documentation
¶
Index ¶
- func Match(program *Pattern, input string) (interface{}, error, int)
- type CapStack
- type CaptureEntry
- type CaptureHandler
- type CaptureResult
- type ConstCapture
- type FunctionCapture
- type IAny
- type IBackCommit
- type ICall
- type IChar
- type ICharset
- type IChoice
- type ICloseCapture
- type ICommit
- type IEmptyCapture
- type IEnd
- type IFail
- type IFailTwice
- type IFullCapture
- type IGiveUp
- type IJump
- type IOpenCall
- type IOpenCapture
- type IPartialCommit
- type IReturn
- type ISpan
- type Instruction
- type ListCapture
- type Pattern
- func And(p *Pattern) *Pattern
- func Any(n int) *Pattern
- func Cconst(value interface{}) *Pattern
- func Cfunc(p *Pattern, f func([]*CaptureResult) (interface{}, error)) *Pattern
- func Char(char byte) *Pattern
- func Clist(p *Pattern) *Pattern
- func Cposition() *Pattern
- func Csimple(p *Pattern) *Pattern
- func Cstring(p *Pattern, format string) *Pattern
- func Csubst(p *Pattern) *Pattern
- func Fail() *Pattern
- func Grm(start string, grammar map[string]*Pattern) *Pattern
- func Lit(text string) *Pattern
- func NegSet(chars string) *Pattern
- func Not(p *Pattern) *Pattern
- func Or(p1, p2 *Pattern) *Pattern
- func Pat(value interface{}) *Pattern
- func Ref(name string) *Pattern
- func Rep(p *Pattern, min, max int) *Pattern
- func Seq(args ...interface{}) *Pattern
- func Seq2(args []interface{}) *Pattern
- func Set(chars string) *Pattern
- func Succ() *Pattern
- func (p *Pattern) Cfunc(f func([]*CaptureResult) (interface{}, error)) *Pattern
- func (p *Pattern) Clist() *Pattern
- func (p *Pattern) Csimple() *Pattern
- func (p *Pattern) Cstring(format string) *Pattern
- func (p *Pattern) Csubst() *Pattern
- func (p *Pattern) Exc(pred *Pattern) *Pattern
- func (p *Pattern) Or(ps ...interface{}) *Pattern
- func (p *Pattern) Rep(min, max int) *Pattern
- func (p *Pattern) Resolve(name string, target *Pattern) *Pattern
- func (p *Pattern) String() string
- type PositionCapture
- type SimpleCapture
- type Stack
- type StackEntry
- type StringCapture
- type SubstCapture
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type CapStack ¶
type CapStack struct {
// contains filtered or unexported fields
}
func NewCapStack ¶
func NewCapStack() *CapStack
func (*CapStack) Close ¶
func (s *CapStack) Close(end int) (*CaptureEntry, int)
Close and return the closest open capture
func (*CapStack) Open ¶
func (s *CapStack) Open(p int, start int) *CaptureEntry
Open and return an new capture
func (*CapStack) Pop ¶
func (s *CapStack) Pop(count int) []*CaptureResult
Pop and return the top `count` captures
type CaptureEntry ¶
type CaptureEntry struct {
// contains filtered or unexported fields
}
type CaptureHandler ¶
type CaptureHandler interface {
Process(input string, start, end int, captures *CapStack, subcaps int) (interface{}, error)
}
Interface for all capture handlers
type CaptureResult ¶
type CaptureResult struct {
// contains filtered or unexported fields
}
Used when returning the values Similar to CaptureEntry, but without some internal values
type ConstCapture ¶
type ConstCapture struct {
// contains filtered or unexported fields
}
Captures a constant value
func (*ConstCapture) String ¶
func (h *ConstCapture) String() string
type FunctionCapture ¶
type FunctionCapture struct {
// contains filtered or unexported fields
}
Calls a function with all sub-captures, and captures the return value. If functions reports an error, let it bubble up.
func (*FunctionCapture) String ¶
func (h *FunctionCapture) String() string
type IAny ¶
type IAny struct {
// contains filtered or unexported fields
}
Match `count` of any character
type IBackCommit ¶
type IBackCommit struct {
// contains filtered or unexported fields
}
Backtracks to a fallback-point, and does a relative jump.
func (*IBackCommit) String ¶
func (op *IBackCommit) String() string
type ICall ¶
type ICall struct {
// contains filtered or unexported fields
}
Push return address to stack, and do a relative jump.
type IChar ¶
type IChar struct {
// contains filtered or unexported fields
}
Match a single character.
type ICharset ¶
type ICharset struct {
// contains filtered or unexported fields
}
Match a character from a set TODO(mizardx): Unicode?
type IChoice ¶
type IChoice struct {
// contains filtered or unexported fields
}
Add a fallback point at offset, and continue on next instruction.
type ICloseCapture ¶
type ICloseCapture struct {
// contains filtered or unexported fields
}
Close the nearest open capture
func (*ICloseCapture) String ¶
func (op *ICloseCapture) String() string
type ICommit ¶
type ICommit struct {
// contains filtered or unexported fields
}
Pop a fallback point, and do a relative jump.
type IEmptyCapture ¶
type IEmptyCapture struct {
// contains filtered or unexported fields
}
Open and close a new empty capture
func (*IEmptyCapture) String ¶
func (op *IEmptyCapture) String() string
type IFailTwice ¶
type IFailTwice struct{}
Roll back to the next closest fallback point.
func (*IFailTwice) String ¶
func (op *IFailTwice) String() string
type IFullCapture ¶
type IFullCapture struct {
// contains filtered or unexported fields
}
Open and close a new capture of fixed size
func (*IFullCapture) String ¶
func (op *IFullCapture) String() string
type IOpenCall ¶
type IOpenCall struct {
// contains filtered or unexported fields
}
Unresolved call. Used by grammars.
type IOpenCapture ¶
type IOpenCapture struct {
// contains filtered or unexported fields
}
Open a new capture
func (*IOpenCapture) String ¶
func (op *IOpenCapture) String() string
type IPartialCommit ¶
type IPartialCommit struct {
// contains filtered or unexported fields
}
Update top stack entry, and do a relative jump.
func (*IPartialCommit) String ¶
func (op *IPartialCommit) String() string
type Instruction ¶
Interface for instructions. XXX(mizardx): Make this more specific?
type ListCapture ¶
type ListCapture struct{}
Captures a list of all sub-captures
func (*ListCapture) String ¶
func (h *ListCapture) String() string
type Pattern ¶
type Pattern []Instruction
func Cfunc ¶
func Cfunc(p *Pattern, f func([]*CaptureResult) (interface{}, error)) *Pattern
Does a function capture.
func Pat ¶
func Pat(value interface{}) *Pattern
Resolve a value to a pattern. Patterns are return unmodified.
- true gives a pattern that always succeeds. Equivalent to Succ().
- false gives a pattern that always fails. Equivalent to Fail().
- n < 0 asserts that there are at least -n characters. Equivalent to And(Any(n)).
- n >= 0 matches n characters. Equivalent to Any(n).
- A string matches itself. Equivalent to Lit(value)
func Seq ¶
func Seq(args ...interface{}) *Pattern
A sequence of values, instructions and other patterns. (See Seq2)
func Seq2 ¶
func Seq2(args []interface{}) *Pattern
A sequence of values, instructions and other patterns Instructions that represent jumps are updated to match the sizes of the argument.
func (*Pattern) Cfunc ¶
func (p *Pattern) Cfunc(f func([]*CaptureResult) (interface{}, error)) *Pattern
A function capture of this pattern.
type PositionCapture ¶
type PositionCapture struct{}
Captures the current input position
func (*PositionCapture) String ¶
func (h *PositionCapture) String() string
type SimpleCapture ¶
type SimpleCapture struct{}
Captures the matched substring
func (*SimpleCapture) String ¶
func (h *SimpleCapture) String() string
type StackEntry ¶
type StackEntry struct {
// contains filtered or unexported fields
}
type StringCapture ¶
type StringCapture struct {
// contains filtered or unexported fields
}
Capture a string created from a format applied to the sub-captures.
func (*StringCapture) String ¶
func (h *StringCapture) String() string
type SubstCapture ¶
type SubstCapture struct{}
Capture a string, with all sub-captures replaced by their string-representation. XXX(mizardx): Better explaination?
func (*SubstCapture) String ¶
func (h *SubstCapture) String() string
Source Files