Predicator.Errors.ParseError (predicator v9.0.0)

Error struct for parse errors in Predicator expressions.

This error occurs when the input expression cannot be parsed due to syntax errors.

Fields

message - Human-readable error description. Never contains the location - that is always :position
position - {line, column} of the syntax error, typed Predicator.Types.position/0 so generic error-reporting code can read a position uniformly across ParseError, EvaluationError, TypeMismatchError, and UndefinedVariableError
span - the source text the failing token or construct covers, when the failure carried a token extent (optional, default nil). position is always the span's start when both are present.

Examples

A parse error from a compile entry point carries all three fields - the span comes from the token stream, so it is present in every compile mode, not only the _with_spans ones:

iex> {:error, error} = Predicator.compile("score > > 5")
iex> {error.position, error.span}
{{1, 9}, {{1, 9}, {1, 10}}}

:span is nil only on an error a caller built through new/3:

iex> Predicator.Errors.ParseError.new("boom", 1, 10)
%Predicator.Errors.ParseError{message: "boom", position: {1, 10}, span: nil}

Summary

Functions

new(message, line, column)

Creates a parse error.

new(message, line, column, span)

Creates a parse error with a source span.

Types

t()

@type t() :: %Predicator.Errors.ParseError{
  message: binary(),
  position: Predicator.Types.position(),
  span: Predicator.Types.span() | nil
}

Functions

new(message, line, column)

@spec new(binary(), pos_integer(), pos_integer()) :: t()

Creates a parse error.

Takes the line and column separately because that is the shape Predicator.Lexer.tokenize/1 and Predicator.Parser.parse/2 report failures in; the struct stores them as a single :position tuple. :span is nil.

new(message, line, column, span)

@spec new(binary(), pos_integer(), pos_integer(), Predicator.Types.span() | nil) ::
  t()

Creates a parse error with a source span.

Like new/3, but also records the token or construct extent the failure covers. :position is set to the span's start.