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spitfire.ex
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defmodule Spitfire do
@moduledoc """
Spitfire parser
"""
import Spitfire.Tracer
import Spitfire.While
import Spitfire.While2
require Logger
@trace? Application.compile_env(:spitfire, :trace, false)
defmodule NoFuelRemaining do
@moduledoc false
defexception message: """
The parser ran out of fuel!
This happens when the parser recurses too many times without consuming a new token,
and most likely indicates a bug in the parser.
"""
end
# precedences
# pratt parsers are top down operator precedence recursive descent parsers
#
# operators have precedence (also known as binding power in some literature) and have a direction, left or right
#
# precedences increment by 2s to account for the left and right binding power. when doing the calculation (as seen in parse_expression/2)
# if an operator has a right binding power, then you subtract 1 before comparing.
# an example to differentiate the two binding powers are to compare the plus and concat operators.
#
# the implicit parentheses in the following two expressions makes this concept clearer
#
# one + two + three => ((one + two) + three)
# and
# one ++ two ++ three => (one ++ (two ++ three))
#
# this is also made evident by comparing the resulting AST
# iex(1)> quote do
# ...(1)> one + two + three
# ...(1)> end
# {:+, [context: Elixir, imports: [{1, Kernel}, {2, Kernel}]],
# [
# {:+, [context: Elixir, imports: [{1, Kernel}, {2, Kernel}]],
# [{:one, [], Elixir}, {:two, [], Elixir}]},
# {:three, [], Elixir}
# ]}
# iex(2)> quote do
# ...(2)> one ++ two ++ three
# ...(2)> end
# {:++, [context: Elixir, imports: [{2, Kernel}]],
# [
# {:one, [], Elixir},
# {:++, [context: Elixir, imports: [{2, Kernel}]],
# [{:two, [], Elixir}, {:three, [], Elixir}]}
# ]}
@lowest {:left, 2}
@doo {:left, 4}
@stab_op {:right, 6}
# list comma are commas inside tuples, maps, and lists, and function parameter/argument lists
@list_comma {:left, 8}
@in_match_op {:left, 10}
@whenn {:right, 12}
# comma are commas inside a right stab argument list
@comma {:left, 14}
@kw_identifier {:left, 16}
@assoc_op {:right, 18}
@type_op {:right, 20}
@pipe_op {:right, 22}
@capture_op {:left, 24}
@match_op {:right, 26}
@or_op {:left, 28}
@and_op {:left, 30}
@comp_op {:left, 32}
@rel_op {:left, 34}
@arrow_op {:left, 36}
@in_op {:left, 38}
@xor_op {:left, 40}
@ternary_op {:right, 42}
@concat_op {:right, 44}
@range_op {:right, 46}
@dual_op {:left, 48}
@mult_op {:left, 50}
@power_op {:left, 52}
@left_paren {:left, 54}
@unary_op {:left, 56}
@left_bracket {:left, 58}
@dot_call_op {:left, 60}
@dot_op {:left, 62}
@at_op {:left, 64}
@precedences %{
:"," => @comma,
:. => @dot_call_op,
:"(" => @left_paren,
:"[" => @left_bracket,
dot_call_op: @dot_call_op,
do: @doo,
kw_identifier: @kw_identifier,
stab_op: @stab_op,
in_match_op: @in_match_op,
when_op: @whenn,
type_op: @type_op,
pipe_op: @pipe_op,
assoc_op: @assoc_op,
capture_op: @capture_op,
match_op: @match_op,
or_op: @or_op,
and_op: @and_op,
comp_op: @comp_op,
rel_op: @rel_op,
arrow_op: @arrow_op,
in_op: @in_op,
xor_op: @xor_op,
ternary_op: @ternary_op,
concat_op: @concat_op,
range_op: @range_op,
dual_op: @dual_op,
mult_op: @mult_op,
power_op: @power_op,
unary_op: @unary_op,
dot_op: @dot_op,
at_op: @at_op
}
@spec parse(String.t(), Keyword.t()) :: {:ok, Macro.t()} | {:error, :no_fuel_remaining} | {:error, Macro.t(), list()}
def parse(code, opts \\ []) do
parser = code |> new(opts) |> next_token() |> next_token()
# eat all the beginning eol tokens in case the file starts with a comment
parser =
while current_token(parser) == :eol <- parser do
next_token(parser)
end
case parse_program(parser) do
{ast, %{errors: []}} ->
{:ok, ast}
{ast, %{errors: errors}} ->
{:error, ast, Enum.reverse(errors)}
end
rescue
NoFuelRemaining ->
{:error, :no_fuel_remaining}
after
Process.delete(:comma_list_parsers)
end
def parse!(code, opts \\ []) do
case parse(code, opts) do
{:ok, ast} ->
ast
{:error, :no_fuel_remaining} ->
raise "No fuel remaining!"
{:error, _ast, _errors} ->
raise "Failed to parse!"
end
end
def parse_with_comments(code, opts \\ []) do
Process.put(:code_formatter_comments, [])
opts = [{:preserve_comments, &preserve_comments/5} | opts]
result = parse(code, opts)
comments = Enum.reverse(Process.get(:code_formatter_comments))
case result do
{:ok, ast} -> {:ok, ast, comments}
{:error, ast, errors} -> {:error, ast, comments, errors}
end
after
Process.delete(:code_formatter_comments)
end
def container_cursor_to_quoted(code, opts \\ []) do
opts =
opts
|> Keyword.put(:cursor_completion, true)
|> Keyword.put(:emit_warnings, false)
|> Keyword.put(:check_terminators, {:cursor, []})
Spitfire.parse(code, opts)
end
defp parse_program(parser) do
trace "parse_program", trace_meta(parser) do
{exprs, parser} =
while2 current_token(parser) != :eof <- parser do
{ast, parser} = parse_expression(parser, @lowest, false, false, true)
parser =
cond do
match?({:__block__, [{:error, true} | _], _}, ast) ->
next_token(parser)
peek_token(parser) in [:eol, :";", :eof] and parser.tokens != :eot ->
next_token(parser)
true ->
parser
end
ast = push_eoe(ast, current_eoe(parser))
{ast, eat_eol(parser)}
end
exprs = build_block_nr(exprs)
{exprs, parser}
end
end
defp calc_prec(parser, associativity, precedence) do
{_associativity, power} = peek_precedence(parser)
precedence =
case associativity do
:left -> precedence
:right -> precedence - 1
end
precedence < power
end
@terminals MapSet.new([:eol, :eof, :"}", :")", :"]", :">>"])
@terminals_with_comma MapSet.put(@terminals, :",")
defp(parse_expression(parser, assoc \\ @lowest, is_list \\ false, is_map \\ false, is_top \\ false, is_stab \\ false))
defp parse_expression(parser, {associativity, precedence}, is_list, is_map, is_top, is_stab) do
trace "parse_expression", trace_meta(parser) do
parser = consume_fuel(parser)
prefix =
case current_token_type(parser) do
:identifier -> &parse_identifier/1
:do_identifier -> &parse_do_identifier/1
:paren_identifier -> &parse_paren_identifier/1
:bracket_identifier -> &parse_lone_identifier/1
:op_identifier -> &parse_identifier/1
:alias -> &parse_alias/1
:"<<" -> &parse_bitstring/1
:kw_identifier when is_list or is_map -> &parse_kw_identifier/1
:kw_identifier_unsafe when is_list or is_map -> &parse_kw_identifier/1
:kw_identifier when not is_list and not is_map -> &parse_bracketless_kw_list/1
:kw_identifier_unsafe when not is_list and not is_map -> &parse_bracketless_kw_list/1
:int -> &parse_int/1
:flt -> &parse_float/1
:atom -> &parse_atom/1
:atom_quoted -> &parse_atom/1
:atom_unsafe -> &parse_atom/1
true -> &parse_boolean/1
false -> &parse_boolean/1
:bin_string -> &parse_string/1
:bin_heredoc -> &parse_string/1
:list_string -> &parse_string/1
:list_heredoc -> &parse_string/1
:char -> &parse_char/1
:sigil -> &parse_sigil/1
:fn -> &parse_anon_function/1
:at_op -> &parse_prefix_expression/1
:unary_op -> &parse_prefix_expression/1
:capture_op -> &parse_prefix_expression/1
:dual_op -> &parse_prefix_expression/1
:capture_int -> &parse_capture_int/1
:stab_op -> &parse_stab_expression/1
:range_op -> &parse_range_expression/1
:"[" -> &parse_list_literal/1
:"(" -> &parse_grouped_expression/1
:"{" -> &parse_tuple_literal/1
:";" -> raise "semicolon"
:%{} -> &parse_map_literal/1
:% -> &parse_struct_literal/1
:ellipsis_op -> &parse_ellipsis_op/1
nil -> &parse_nil_literal/1
_ -> nil
end
if prefix == nil do
meta = current_meta(parser)
ctype = current_token_type(parser)
parser = put_error(parser, {meta, "unknown token: #{ctype}"})
parser =
case ctype do
:")" -> parser
:"]" -> parser
:"}" -> parser
:">>" -> parser
:end -> parser
_ -> next_token(parser)
end
{{:__block__, [{:error, true} | meta], []}, parser}
else
{left, parser} = prefix.(parser)
terminals =
if is_top do
@terminals
else
@terminals_with_comma
end
{parser, is_valid} = validate_peek(parser, current_token_type(parser))
if is_valid do
while (is_nil(Map.get(parser, :stab_state)) and not MapSet.member?(terminals, peek_token(parser))) &&
(current_token(parser) != :do and peek_token(parser) != :eol) &&
calc_prec(parser, associativity, precedence) <- {left, parser} do
parser = consume_fuel(parser)
peek_token_type = peek_token_type(parser)
infix =
case peek_token_type do
:match_op -> &parse_infix_expression/2
:when_op -> &parse_infix_expression/2
:pipe_op when is_map -> &parse_pipe_op/2
:pipe_op -> &parse_infix_expression/2
:type_op -> &parse_infix_expression/2
:dual_op -> &parse_infix_expression/2
:mult_op -> &parse_infix_expression/2
:power_op -> &parse_infix_expression/2
:"[" -> &parse_access_expression/2
:concat_op -> &parse_infix_expression/2
:assoc_op -> &parse_assoc_op/2
:arrow_op -> &parse_infix_expression/2
:ternary_op -> &parse_infix_expression/2
:or_op -> &parse_infix_expression/2
:and_op -> &parse_infix_expression/2
:comp_op -> &parse_infix_expression/2
:rel_op -> &parse_infix_expression/2
:in_op -> &parse_infix_expression/2
:xor_op -> &parse_infix_expression/2
:in_match_op -> &parse_infix_expression/2
:range_op -> &parse_range_expression/2
:stab_op when not is_stab -> &parse_stab_expression/2
:do -> &parse_do_block/2
:dot_call_op -> &parse_dot_call_expression/2
:"(" -> &parse_call_expression/2
:. -> &parse_dot_expression/2
:"," when is_top -> &parse_comma/2
_ -> nil
end
do_block = &parse_do_block/2
case infix do
nil when is_stab and peek_token_type == :stab_op ->
parser = Map.put(parser, :stab_state, %{ast: left})
# this will be ignored on the return
{left, parser}
nil ->
{left, parser}
^do_block when parser.nesting != 0 ->
{left, next_token(parser)}
_ ->
infix.(next_token(parser), left)
end
end
else
{left, parser}
end
end
end
end
defp parse_grouped_expression(parser) do
trace "parse_grouped_expression", trace_meta(parser) do
opening_paren_meta = current_meta(parser)
if peek_token(parser) == :")" do
parser = parser |> next_token() |> eat_eol()
closing_paren_meta = current_meta(parser)
{{:__block__, [parens: opening_paren_meta ++ [closing: closing_paren_meta]], []}, parser}
else
orig_meta = current_meta(parser)
parser = parser |> next_token() |> eat_eol()
old_nesting = parser.nesting
parser = Map.put(parser, :nesting, 0)
{expression, parser} = parse_expression(parser, @lowest, false, false, true)
expression = push_eoe(expression, peek_eoe(parser))
cond do
# if the next token is the closing paren or if the next token is a newline and the next next token is the closing paren
peek_token(parser) == :")" || (peek_token(parser) == :eol && peek_token(next_token(parser)) == :")") ->
parser =
parser
|> Map.put(:nesting, old_nesting)
|> next_token()
|> eat_eol()
closing_paren_meta = current_meta(parser)
ast =
case expression do
# unquote splicing is special cased, if it has one expression as an arg, its wrapped in a block
{:unquote_splicing, _, [_]} ->
{:__block__, [{:closing, current_meta(parser)} | orig_meta], [expression]}
# not and ! are special cased, if it has one expression as an arg, its wrapped in a block
{op, _, [_]} when op in [:not, :!] ->
{:__block__, [], [expression]}
{:->, _, _} ->
[expression]
{f, meta, a} ->
{f, [parens: opening_paren_meta ++ [closing: closing_paren_meta]] ++ meta, a}
expression ->
expression
end
{ast, parser}
# if the next token is a new line, but the next next token is not the closing paren (implied from previous clause)
peek_token(parser) == :eol or current_token(parser) == :-> ->
# second conditon checks of the next next token is a closing paren or another expression
{exprs, parser} =
while2 current_token(parser) == :-> ||
(peek_token(parser) == :eol && parser |> next_token() |> peek_token() != :")") <- parser do
{ast, parser} =
case Map.get(parser, :stab_state) do
%{ast: lhs} ->
{ast, parser} = parse_stab_expression(Map.delete(parser, :stab_state), lhs)
{ast, parser} =
if current_token(parser) == :-> do
{ast, parser}
else
if peek_token(parser) == :")" do
{ast, parser}
else
eoe = current_eoe(parser)
ast = push_eoe(ast, eoe)
{ast, next_token(parser)}
end
end
{ast, parser}
nil ->
parser = parser |> next_token() |> eat_eol()
{ast, parser} = parse_expression(parser, @lowest, false, false, true)
{ast, parser} =
cond do
current_token(parser) == :-> ->
{ast, parser}
peek_token(parser) == :")" ->
{ast, parser}
true ->
eoe = peek_eoe(parser)
ast = push_eoe(ast, eoe)
{ast, parser}
end
{ast, parser}
end
{ast, parser}
end
# handles if the closing paren is on a new line or the same line
parser =
if peek_token(parser) == :eol do
next_token(parser)
else
parser
end
if peek_token(parser) == :")" do
parser =
parser
|> Map.put(:nesting, old_nesting)
|> next_token()
exprs = [expression | exprs]
ast =
case exprs do
[{:->, _, _} | _] ->
exprs
_ ->
{:__block__, [{:closing, current_meta(parser)} | orig_meta], exprs}
end
{ast, parser}
else
meta = current_meta(parser)
parser =
parser
|> put_error({meta, "missing closing parentheses"})
|> Map.put(:nesting, old_nesting)
{{:__block__, [{:error, true} | meta], []}, next_token(parser)}
end
true ->
meta = current_meta(parser)
parser =
parser
|> put_error({meta, "missing closing parentheses"})
|> Map.put(:nesting, old_nesting)
{{:__block__, [{:error, true} | meta], []}, next_token(parser)}
end
end
end
end
defp parse_nil_literal(%{current_token: {nil, meta}} = parser) do
trace "parse_nil_literal", trace_meta(parser) do
ast = encode_literal(parser, nil, meta)
{ast, parser}
end
end
defp parse_kw_identifier(%{current_token: {:kw_identifier, meta, token}} = parser) do
trace "parse_kw_identifier", trace_meta(parser) do
token = encode_literal(parser, token, meta)
parser = parser |> next_token() |> eat_eol()
{expr, parser} = parse_expression(parser, @kw_identifier, false, false, false)
{{token, expr}, parser}
end
end
defp parse_kw_identifier(%{current_token: {:kw_identifier_unsafe, meta, tokens}} = parser) do
trace "parse_kw_identifier (unsafe)", trace_meta(parser) do
{atom, parser} = parse_atom(%{parser | current_token: {:atom_unsafe, meta, tokens}})
parser = parser |> next_token() |> eat_eol()
{expr, parser} = parse_expression(parser, @kw_identifier, false, false, false)
atom =
case atom do
{t, meta, args} ->
{delimiter, meta} = Keyword.pop(meta, :delimiter)
meta = meta |> Keyword.put(:format, :keyword) |> Keyword.put(:delimiter, delimiter)
{t, meta, args}
end
{{atom, expr}, parser}
end
end
defp parse_bracketless_kw_list(%{current_token: {:kw_identifier, meta, token}} = parser) do
trace "parse_bracketless_kw_list", trace_meta(parser) do
token = encode_literal(parser, token, meta)
parser = parser |> next_token() |> eat_eol()
{value, parser} = parse_expression(parser, @kw_identifier, false, false, false)
{kvs, parser} =
while2 peek_token(parser) == :"," <- parser do
parser = parser |> next_token() |> next_token()
{pair, parser} = parse_kw_identifier(parser)
{pair, parser}
end
{[{token, value} | kvs], parser}
end
end
defp parse_bracketless_kw_list(%{current_token: {:kw_identifier_unsafe, meta, tokens}} = parser) do
trace "parse_bracketless_kw_list (unsafe)", trace_meta(parser) do
{atom, parser} = parse_atom(%{parser | current_token: {:atom_unsafe, meta, tokens}})
parser = parser |> next_token() |> eat_eol()
atom =
case atom do
{t, meta, args} ->
{delimiter, meta} = Keyword.pop(meta, :delimiter)
meta = meta |> Keyword.put(:format, :keyword) |> Keyword.put(:delimiter, delimiter)
{t, meta, args}
end
{value, parser} = parse_expression(parser, @kw_identifier, false, false, false)
{kvs, parser} =
while2 peek_token(parser) == :"," <- parser do
parser = parser |> next_token() |> next_token()
{pair, parser} = parse_kw_identifier(parser)
{pair, parser}
end
{[{atom, value} | kvs], parser}
end
end
defp parse_assoc_op(%{current_token: {:assoc_op, _, _token}} = parser, key) do
trace "parse_assoc_op", trace_meta(parser) do
assoc_meta = current_meta(parser)
parser = parser |> next_token() |> eat_eol()
{value, parser} = parse_expression(parser, @assoc_op, false, false, false)
key =
case key do
{f, meta, args} ->
{f, [{:assoc, assoc_meta} | meta], args}
_ ->
key
end
{{key, value}, parser}
end
end
defp(parse_comma_list(parser, precedence \\ @list_comma, is_list \\ false, is_map \\ false))
defp parse_comma_list(parser, precedence, is_list, is_map) do
trace "parse_comma_list", trace_meta(parser) do
{front, parser} = parse_expression(parser, precedence, is_list, is_map, false)
# we zip together the expression and parser state so that we can potentially
# backtrack later
Process.put(:comma_list_parsers, [parser])
{items, parser} =
while2 peek_token(parser) == :"," <- parser do
parser = next_token(parser)
case peek_token(parser) do
delimiter when delimiter in [:"]", :"}"] ->
{:filter, {nil, parser}}
_ ->
parser = next_token(parser)
{item, parser} = parse_expression(parser, precedence, is_list, is_map, false)
clp = Process.get(:comma_list_parsers)
Process.put(:comma_list_parsers, [parser | clp])
{item, parser}
end
end
{[front | items], parser}
end
end
defp parse_prefix_expression(parser) do
trace "parse_prefix_expression", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
precedence =
if current_token_type(parser) == :dual_op do
# dual ops are treated as unary ops when being used as a prefix operator
@unary_op
else
current_precedence(parser)
end
parser = parser |> next_token() |> eat_eol()
{rhs, parser} = parse_expression(parser, precedence, false, false, false)
ast = {token, meta, [rhs]}
{ast, parser}
end
end
defp parse_prefix_lone_identifer(parser) do
trace "parse_prefix_lone_identifer", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
parser = next_token(parser)
{rhs, parser} = parse_lone_identifier(parser)
ast = {token, meta, [rhs]}
{ast, parser}
end
end
defp parse_capture_int(parser) do
trace "parse_capture_int", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
parser = next_token(parser)
{encoder, parser} = Map.pop(parser, :literal_encoder)
{rhs, parser} = parse_int(parser)
parser = Map.put(parser, :literal_encoder, encoder)
ast = {token, meta, [rhs]}
{ast, parser}
end
end
# """
# A stab expression without a lhs is only possible as the argument to an anonymous function and in the typespect of an anon function
# ```elixir
# fn -> :ok end
# @spec start_link((-> term), GenServer.options()) :: on_start
# ```
# """
defp parse_stab_expression(parser) do
trace "parse_stab_expression", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
newlines = get_newlines(parser)
parser = eat_at(parser, [:eol, :";"], 1)
old_nesting = parser.nesting
parser = Map.put(parser, :nesting, 0)
{exprs, parser} =
while2 peek_token(parser) not in [:end, :")"] <- parser do
parser = parser |> next_token() |> eat_eol()
{ast, parser} = parse_expression(parser, @lowest, false, false, true)
eoe = peek_eoe(parser)
parser = eat_eol_at(parser, 1)
ast = push_eoe(ast, eoe)
{ast, parser}
end
rhs = build_block_nr(exprs)
ast =
{token, newlines ++ meta, [[], rhs]}
parser = Map.put(parser, :nesting, old_nesting)
{ast, parser}
end
end
# """
# A stab expression with a lhs is present in case, cond, and try blocks, as well as macros and typespecs.
# The rhs of a stab expression can be a single expression or a block of expressions. The end of the
# block is denoted by either the `end` keyword or by the start of another "bare" stab expression.
# ```elixir
# case foo do
# :bar ->
# Some.thing()
# :ok
# :baz ->
# Another.thing()
# :error
# end
# ```
# """
defp parse_stab_expression(parser, lhs) do
trace "parse_stab_expression (with lhs)", trace_meta(parser) do
case current_token(parser) do
:<- ->
parse_infix_expression(parser, lhs)
:-> ->
token = current_token(parser)
meta = current_meta(parser)
newlines = get_newlines(parser)
parser = eat_eol_at(parser, 1)
old_nesting = parser.nesting
parser = Map.put(parser, :nesting, 0)
{exprs, parser} =
while2 Map.get(parser, :stab_state) == nil and peek_token(parser) not in [:eof, :end, :")", :block_identifier] <-
parser do
parser = next_token(parser)
{ast, parser} = parse_expression(parser, @lowest, false, false, true, true)
if Map.get(parser, :stab_state) == nil do
eoe = peek_eoe(parser)
ast = push_eoe(ast, eoe)
parser = eat_eol_at(parser, 1)
{ast, eat_eol(parser)}
else
{:filter, {nil, next_token(parser)}}
end
end
rhs = build_block_nr(exprs)
meta =
case lhs do
{type, [{:parens, _parens} = paren_meta | _], _} when type in [:__block__, :comma] ->
[paren_meta | meta]
_ ->
meta
end
lhs =
case lhs do
{:__block__, _, []} -> []
{:comma, _, lhs} -> lhs
lhs -> [lhs]
end
meta = newlines ++ meta
ast =
{token, meta, [lhs, rhs]}
parser = Map.put(parser, :nesting, old_nesting)
{ast, eat_eol(parser)}
end
end
end
defp parse_comma(parser, lhs) do
trace "parse_comma", trace_meta(parser) do
parser = parser |> next_token() |> eat_eol()
{exprs, parser} = parse_comma_list(parser, @comma)
{{:comma, [], [lhs | exprs]}, eat_eol(parser)}
end
end
defp parse_infix_expression(parser, lhs) do
trace "parse_infix_expression", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
precedence = current_precedence(parser)
# we save this in case the next expression is an error
pre_parser = parser
newlines =
case current_newlines(parser) || peek_newlines(parser, :eol) do
nil -> []
nl -> [newlines: nl]
end
parser = parser |> next_token() |> eat_eol()
{rhs, parser} = parse_expression(parser, precedence, false, false, false)
{rhs, parser} =
case rhs do
{:__block__, [{:error, true} | _], []} ->
parser = put_error(pre_parser, {meta, "malformed right-hand side of #{token} operator"})
{{:__block__, [{:error, true} | meta], []}, parser}
_ ->
{rhs, parser}
end
ast =
case token do
:"not in" ->
{:not, meta, [{:in, meta, [lhs, rhs]}]}
:when ->
lhs =
case lhs do
{:comma, _, lhs} -> lhs
lhs -> [lhs]
end
{token, newlines ++ meta, lhs ++ [rhs]}
_ ->
{token, newlines ++ meta, [lhs, rhs]}
end
{ast, parser}
end
end
defp parse_pipe_op(parser, lhs) do
trace "parse_pipe_op", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
newlines =
case current_newlines(parser) || peek_newlines(parser, :eol) do
nil -> []
nl -> [newlines: nl]
end
parser = next_token(parser)
parser = eat_eol(parser)
{pairs, parser} = parse_comma_list(parser, @list_comma, false, true)
ast = {token, newlines ++ meta, [lhs, pairs]}
{ast, parser}
end
end
defp parse_access_expression(parser, lhs) do
trace "parse_access_expression", trace_meta(parser) do
meta = current_meta(parser)
parser = parser |> next_token() |> eat_eol()
{rhs, parser} = parse_expression(parser, @lowest, false, false, false)
extra_meta = [from_brackets: true]
newlines =
case peek_newlines(parser, :eol) do
nil -> []
nl -> [newlines: nl]
end
parser = parser |> next_token() |> eat_eol()
closing = current_meta(parser)
meta = extra_meta ++ newlines ++ [{:closing, closing} | meta]
ast = {{:., meta, [Access, :get]}, meta, [lhs, rhs]}
{ast, parser}
end
end
defp parse_range_expression(parser) do
trace "parse_range_expression", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
{{token, meta, []}, parser}
end
end
defp parse_range_expression(parser, lhs) do
trace "parse_range_expression (with lhs)", trace_meta(parser) do
token = current_token(parser)
meta = current_meta(parser)
precedence = current_precedence(parser)
parser = next_token(parser)
{rhs, parser} = parse_expression(parser, precedence, false, false, false)
if peek_token(parser) == :ternary_op do
parser = parser |> next_token() |> next_token()
{rrhs, parser} = parse_expression(parser, precedence, false, false, false)
{{:..//, meta, [lhs, rhs, rrhs]}, eat_eol(parser)}
else
{{token, meta, [lhs, rhs]}, eat_eol(parser)}
end
end
end
# Do Block Algorithm: The Movie
#
# A do block consists of the keyword `do`, following by 0 or more expressions
# separated by newlines/semicolons, followed by 0 or more block identifier
# (else, rescue, after, catch) + 0 or more expressions separated by newlines/semicolons
# and concluded with the keyword `end`
#
# - beginning of parse function, current_token = :do
# - encode `:do` literal in case of literal_encoder
# - save the old nesting level and insert a 0
# - enter outer loop
# - the job of the outer loop is to collect the expressions for each do+block_identifier
# (from now on just referred to as block_identifier)
# - else, start inner loop
# - each iteration of the loop continues if the peek token (while eating an eol) is not in end, block_identifier, or eof
# - increment the token, and eat the eol token
# - if the current token is end or a block_identifier, then the expression
# list is empty. return the expressions and end the iteration
# - else, parse the current expression
# - each iteration of the loop continues if the peek token is not in end, block_identifier, or eof
# - increment the token, and eat the eol token
# - if stab_state
# - we are in the body of a stab expression, don't increment and parse the stab
# - else
# - parse expression
# - push eoe of the next token, but don't actually increment the parser