José Valim
f1e2fcf9f9
Prior to this commit, the following code would work:
defmodule Hello do
defmacro write do
quote do
a = 1
end
end
defmacro read do
quote do
a
end
end
end
require Hello
Hello.write
Hello.read
Although this is convenient, it has many issues:
1. It is not clear at any point the intent of sharing the variables
in between the macros
2. Whenever macros from the same module are nested, there is a chance
a variable used before and after the nesting to be overriden
We address this issue by only allowing variables explicitly marked
with var! to be shared. Here is how the example above should be updated:
defmodule Hello do
defmacro write do
quote do
var!(a, Hello) = 1
end
end
defmacro read do
quote do
var!(a, Hello)
end
end
end
require Hello
Hello.write
Hello.read
86 lines
3.4 KiB
Erlang
86 lines
3.4 KiB
Erlang
-define(wrap_call(Line, Module, Function, Args),
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{ call, Line,
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{ remote, Line, { atom, Line, Module }, { atom, Line, Function } },
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Args
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}).
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-define(atom_concat(Atoms), list_to_atom(lists:concat(Atoms))).
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-define(elixir_macro(Macro), list_to_atom(lists:concat(['MACRO-',Macro]))).
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-define(line(Opts), elixir_utils:get_line(Opts)).
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-record(elixir_scope, {
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context=nil, %% can be assign, guards or nil
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extra=nil, %% extra information about the context, like fn_match for fns
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noname=false, %% when true, don't add new names (used by try)
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super=false, %% when true, it means super was invoked
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caller=false, %% when true, it means caller was invoked
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module=nil, %% the current module
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function=nil, %% the current function
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vars=[], %% a dict of defined variables and their alias
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backup_vars=nil, %% a copy of vars to be used on ^var
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temp_vars=nil, %% a set of all variables defined in a particular assign
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clause_vars=nil, %% a dict of all variables defined in a particular clause
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extra_guards=nil, %% extra guards from args expansion
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counter=[], %% a counter for the variables defined
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local=nil, %% the scope to evaluate local functions against
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context_modules=[], %% modules defined in the current context
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macro_aliases=[], %% keep aliases defined inside a macro
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macro_counter=0, %% macros expansions counter
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aliases, %% an orddict with aliases by new -> old names
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file, %% the current scope filename
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requires, %% a set with modules required
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macro_macros=[], %% a list with macros imported from module inside a macro
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macros, %% a list with macros imported from module
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macro_functions=[], %% a list with functions imported from module inside a macro
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functions %% a list with functions imported from module
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}).
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-record(elixir_quote, {
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line=nil,
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context=nil,
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vars_hygiene=true,
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aliases_hygiene=true,
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imports_hygiene=true,
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unquote=true,
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unquoted=false,
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escape=false
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}).
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-record(elixir_tokenizer, {
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file,
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terminators=[],
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check_terminators=true,
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existing_atoms_only=false
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}).
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%% Introspection
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-define(defs(Kind), Kind == def; Kind == defp; Kind == defmacro; Kind == defmacrop).
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%% Used in tokenization and interpolation
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%% Numbers
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-define(is_hex(S), ?is_digit(S) orelse (S >= $A andalso S =< $F) orelse (S >= $a andalso S =< $f)).
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-define(is_bin(S), S >= $0 andalso S =< $1).
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-define(is_octal(S), S >= $0 andalso S =< $7).
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-define(is_leading_octal(S), S >= $0 andalso S =< $3).
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%% Digits and letters
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-define(is_digit(S), S >= $0 andalso S =< $9).
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-define(is_upcase(S), S >= $A andalso S =< $Z).
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-define(is_downcase(S), S >= $a andalso S =< $z).
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%% Atoms
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-define(is_atom_start(S), ?is_quote(S) orelse ?is_upcase(S) orelse ?is_downcase(S) orelse (S == $_)).
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-define(is_atom(S), ?is_identifier(S) orelse (S == $@)).
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-define(is_identifier(S), ?is_digit(S) orelse ?is_upcase(S) orelse ?is_downcase(S) orelse (S == $_)).
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-define(is_terminator(S), (S == $?) orelse (S == $!) orelse (S == $:)).
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%% Quotes
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-define(is_quote(S), S == $" orelse S == $').
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%% Spaces
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-define(is_horizontal_space(S), (S == $\s) orelse (S == $\t)).
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-define(is_vertical_space(S), (S == $\r) orelse (S == $\n)).
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-define(is_space(S), ?is_horizontal_space(S) orelse ?is_vertical_space(S)).
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