Documentation
¶
Overview ¶
Package parser implements R7RS Scheme syntax parsing.
The parser converts a token stream into syntax values with source location:
Features ¶
- All Scheme datums: literals, symbols, lists, vectors, bytevectors
- Full numeric tower: integers, floats, rationals, complex, big numbers
- Quote forms: ', `, ,, ,@ and syntax variants #', #`, #,, #,@
- Datum labels: #n= and #n# for shared/circular structures (R7RS 2.4)
- Case folding: #!fold-case and #!no-fold-case directives
- Symbol interning at parse time
Usage ¶
p := parser.NewParserWithFile(env, true, reader, "example.scm")
for {
stx, err := p.ReadSyntax(ctx)
if err == io.EOF {
break
}
// process stx
}
Error Handling ¶
Parse errors are wrapped in ParserError with source location from the offending token. The parser accumulates no state across expressions.
Index ¶
- Constants
- Variables
- func ParseComplexStringNumber(s string) (values.Number, bool)
- func ParseImaginaryStringNumber(s string) (values.Number, bool)
- func ParseSpecialFloat(s string) (*values.Float, bool)
- type Parser
- type ParserError
- func NewParserError(tok tokenizer.Token, mess string) *ParserError
- func NewParserErrorWithWrap(err error, tok tokenizer.Token, mess string) *ParserError
- func NewParserErrorWithWrapf(err error, tok tokenizer.Token, mess string, vs ...any) *ParserError
- func NewParserErrorf(tok tokenizer.Token, mess string, vs ...any) *ParserError
Constants ¶
const ( ConstQuote = "quote" ConstQuasiquote = "quasiquote" ConstUnquote = "unquote" ConstUnquoteSplicing = "unquote-splicing" ConstSyntax = "syntax" ConstQuasisyntax = "quasisyntax" ConstUnsyntax = "unsyntax" ConstUnsyntaxSplicing = "unsyntax-splicing" )
Quote form identifiers.
const (
ParserNumberDefaultBase = 10
)
Variables ¶
var ( // ErrUnknownTokenType is returned when the parser encounters an unrecognized token. ErrUnknownTokenType = werr.NewStaticError("unknown token type") ErrAlreadyClosed = werr.NewStaticError("parser already closed") )
Functions ¶
func ParseComplexStringNumber ¶ added in v1.5.0
ParseComplexStringNumber parses a rectangular complex number string ending in 'i'. Handles "3+4i", "1.5-2.5i", "1+inf.0i", "0+3/4i", etc. Returns (nil, false) if s cannot be parsed as a complex number.
func ParseImaginaryStringNumber ¶ added in v1.5.0
ParseImaginaryStringNumber parses a pure imaginary string (ending in 'i') and returns the resulting complex number. Handles "+3i", "-2.5i", "+i", "-i", "+inf.0i", "-nan.0i", etc. Returns (nil, false) if s cannot be parsed as a pure imaginary number.
Types ¶
type Parser ¶
type Parser struct {
// contains filtered or unexported fields
}
Parser represents a R7RS compliant Scheme syntax parser.
func NewParser ¶
func NewParser(env *environment.EnvironmentFrame, skipComments bool, rdr io.RuneReader) *Parser
NewParser creates a new parser for the given reader and environment.
func NewParserWithFile ¶
func NewParserWithFile(env *environment.EnvironmentFrame, skipComments bool, rdr io.RuneReader, file string) *Parser
NewParserWithFile creates a new parser with a specified source filename.
func (*Parser) ReadSyntax ¶
ReadSyntax reads and returns the next syntax value from the input.
type ParserError ¶
type ParserError struct {
// contains filtered or unexported fields
}
ParserError represents an error that occurred during parsing.
func NewParserError ¶
func NewParserError(tok tokenizer.Token, mess string) *ParserError
NewParserError creates a new parser error for the given token.
func NewParserErrorWithWrap ¶
func NewParserErrorWithWrap(err error, tok tokenizer.Token, mess string) *ParserError
NewParserErrorWithWrap creates a new parser error wrapping another error.
func NewParserErrorWithWrapf ¶
NewParserErrorWithWrapf creates a new parser error wrapping another error.
func NewParserErrorf ¶
func NewParserErrorf(tok tokenizer.Token, mess string, vs ...any) *ParserError
NewParserErrorf creates a new parser error for the given token.
func (*ParserError) Error ¶
func (p *ParserError) Error() string
func (*ParserError) Is ¶
func (p *ParserError) Is(err error) bool
Is implements errors.Is for ParserError.
func (*ParserError) IsVoid ¶
func (p *ParserError) IsVoid() bool
func (*ParserError) SchemeString ¶
func (p *ParserError) SchemeString() string
func (*ParserError) Unwrap ¶
func (p *ParserError) Unwrap() error
Source Files