parser

Documentation

Overview

Package parser provides the lexer and parser for the English programming language.

Package parser – human-readable error messages and hint strings.

Every message that can be shown to a programmer when their code contains a syntax error lives here. Edit this file to improve wording, add extra examples, or translate the text – no other file needs to change.

Convention

• msg* constants are the primary error description ("what went wrong").
• hint* constants give corrective guidance ("how to fix it").
• msgFmt* / hintFmt* constants are fmt.Sprintf format strings whose %s / %q placeholders are filled in by the call site using runtime token values.

Index

• type Lexer
  • func NewLexer(input string) *Lexer
• type Parser
  • func NewParser(tokens []token.Token) *Parser
  • func (p *Parser) Parse() (*ast.Program, error)
• type SyntaxError
  • func (e *SyntaxError) Error() string
  • func (e *SyntaxError) SyntaxCol() int
  • func (e *SyntaxError) SyntaxHint() string
  • func (e *SyntaxError) SyntaxLine() int
  • func (e *SyntaxError) SyntaxMessage() string

Types

type Lexer

type Lexer = tokeniser.Lexer

Lexer is a type alias for the shared tokeniser.Lexer so that all existing callers (cmd, vm, lsp, transpiler …) continue to work without change while both the parser and the highlight package share a single tokenisation implementation.

func NewLexer

func NewLexer(input string) *Lexer

NewLexer creates a new Lexer for the given input.

type Parser

type Parser struct {
	// contains filtered or unexported fields
}

Parser transforms tokens into an AST

func NewParser

func NewParser(tokens []token.Token) *Parser

NewParser creates a new parser for the given tokens

func (*Parser) Parse

func (p *Parser) Parse() (*ast.Program, error)

Parse parses the tokens and returns the AST

type SyntaxError

type SyntaxError struct {
	Msg  string // human-readable description of what went wrong
	Line int    // 1-based source line (0 = unknown)
	Col  int    // 1-based source column (0 = unknown)
	Hint string // optional guidance for the programmer
}

SyntaxError is a structured parse-time error. It satisfies the stacktraces.SyntaxError interface so the renderer can display it with a dedicated "Syntax Error" header, line/column information, and an optional user-friendly hint.

func (*SyntaxError) Error

func (e *SyntaxError) Error() string

Error implements the standard error interface.

func (*SyntaxError) SyntaxCol

func (e *SyntaxError) SyntaxCol() int

SyntaxCol implements stacktraces.SyntaxError.

func (*SyntaxError) SyntaxHint

func (e *SyntaxError) SyntaxHint() string

SyntaxHint implements stacktraces.SyntaxError.

func (*SyntaxError) SyntaxLine

func (e *SyntaxError) SyntaxLine() int

SyntaxLine implements stacktraces.SyntaxError.

func (*SyntaxError) SyntaxMessage

func (e *SyntaxError) SyntaxMessage() string

SyntaxMessage implements stacktraces.SyntaxError.