diff options
Diffstat (limited to 'lib/compiler/src/cerl_trees.erl')
| -rw-r--r-- | lib/compiler/src/cerl_trees.erl | 109 |
1 files changed, 108 insertions, 1 deletions
diff --git a/lib/compiler/src/cerl_trees.erl b/lib/compiler/src/cerl_trees.erl index f30a0b33ac..c7a129b42c 100644 --- a/lib/compiler/src/cerl_trees.erl +++ b/lib/compiler/src/cerl_trees.erl @@ -22,7 +22,8 @@ -module(cerl_trees). -export([depth/1, fold/3, free_variables/1, get_label/1, label/1, label/2, - map/2, mapfold/3, mapfold/4, size/1, variables/1]). + map/2, mapfold/3, mapfold/4, next_free_variable_name/1, + size/1, variables/1]). -import(cerl, [alias_pat/1, alias_var/1, ann_c_alias/3, ann_c_apply/3, ann_c_binary/2, ann_c_bitstr/6, ann_c_call/4, @@ -507,6 +508,7 @@ mapfold_pairs(_, _, S, []) -> %% well-formed Core Erlang syntax tree. %% %% @see free_variables/1 +%% @see next_free_variable_name/1 -spec variables(cerl:cerl()) -> [cerl:var_name()]. @@ -519,6 +521,7 @@ variables(T) -> %% @doc Like <code>variables/1</code>, but only includes variables %% that are free in the tree. %% +%% @see next_free_variable_name/1 %% @see variables/1 -spec free_variables(cerl:cerl()) -> [cerl:var_name()]. @@ -678,6 +681,110 @@ var_list_names([V | Vs], A) -> var_list_names([], A) -> A. +%% --------------------------------------------------------------------- + +%% @spec next_free_variable_name(Tree::cerl()) -> var_name() +%% +%% var_name() = integer() +%% +%% @doc Returns a integer variable name higher than any other integer +%% variable name in the syntax tree. An exception is thrown if +%% <code>Tree</code> does not represent a well-formed Core Erlang +%% syntax tree. +%% +%% @see variables/1 +%% @see free_variables/1 + +-spec next_free_variable_name(cerl:cerl()) -> integer(). + +next_free_variable_name(T) -> + 1 + next_free(T, -1). + +next_free(T, Max) -> + case type(T) of + literal -> + Max; + var -> + case var_name(T) of + Int when is_integer(Int) -> + max(Int, Max); + _ -> + Max + end; + values -> + next_free_in_list(values_es(T), Max); + cons -> + next_free(cons_hd(T), next_free(cons_tl(T), Max)); + tuple -> + next_free_in_list(tuple_es(T), Max); + map -> + next_free_in_list([map_arg(T)|map_es(T)], Max); + map_pair -> + next_free_in_list([map_pair_op(T),map_pair_key(T), + map_pair_val(T)], Max); + 'let' -> + Max1 = next_free(let_body(T), Max), + Max2 = next_free_in_list(let_vars(T), Max1), + next_free(let_arg(T), Max2); + seq -> + next_free(seq_arg(T), + next_free(seq_body(T), Max)); + apply -> + next_free(apply_op(T), + next_free_in_list(apply_args(T), Max)); + call -> + next_free(call_module(T), + next_free(call_name(T), + next_free_in_list( + call_args(T), Max))); + primop -> + next_free_in_list(primop_args(T), Max); + 'case' -> + next_free(case_arg(T), + next_free_in_list(case_clauses(T), Max)); + clause -> + Max1 = next_free(clause_guard(T), + next_free(clause_body(T), Max)), + next_free_in_list(clause_pats(T), Max1); + alias -> + next_free(alias_var(T), + next_free(alias_pat(T), Max)); + 'fun' -> + next_free(fun_body(T), + next_free_in_list(fun_vars(T), Max)); + 'receive' -> + Max1 = next_free_in_list(receive_clauses(T), + next_free(receive_timeout(T), Max)), + next_free(receive_action(T), Max1); + 'try' -> + Max1 = next_free(try_body(T), Max), + Max2 = next_free_in_list(try_vars(T), Max1), + Max3 = next_free(try_handler(T), Max2), + Max4 = next_free_in_list(try_evars(T), Max3), + next_free(try_arg(T), Max4); + 'catch' -> + next_free(catch_body(T), Max); + binary -> + next_free_in_list(binary_segments(T), Max); + bitstr -> + next_free(bitstr_val(T), next_free(bitstr_size(T), Max)); + letrec -> + Max1 = next_free_in_defs(letrec_defs(T), Max), + Max2 = next_free(letrec_body(T), Max1), + next_free_in_list(letrec_vars(T), Max2); + module -> + next_free_in_defs(module_defs(T), Max) + end. + +next_free_in_list([H | T], Max) -> + next_free_in_list(T, next_free(H, Max)); +next_free_in_list([], Max) -> + Max. + +next_free_in_defs([{_, Post} | Ds], Max) -> + next_free_in_defs(Ds, next_free(Post, Max)); +next_free_in_defs([], Max) -> + Max. %% --------------------------------------------------------------------- |