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authorBjörn Gustavsson <[email protected]>2016-03-01 06:23:36 +0100
committerBjörn Gustavsson <[email protected]>2016-03-01 13:59:22 +0100
commit205405f0bf1d2fa37d4c8170c11689a2937f5d9c (patch)
treea55b2a94a43ecf521db5c06a41be2af0a0eda44b /lib/tools/test
parent156aea75186fe9de64b87c2c6919db9abf4a0d60 (diff)
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Generalize bit string comprehensions
The expression in a bit string comprehension is limited to a literal bit string expression. That is, the following code is legal: << <<X>> || X <- List >> but not this code: << foo(X) || X <- List >> The limitation is annoying. For one thing, tools that transform the abstract format must be careful not to produce code such as: << begin %% Some instrumentation code. <<X>> end || X <- List >> One reason for the limitation could be that we'll get reduce/reduce conflicts if we try to allow an arbitrary expression in a bit string comprehension: binary_comprehension -> '<<' expr '||' lc_exprs '>>' : {bc,?anno('$1'),'$2','$4'}. Unfortunately, there does not seem to be an easy way to work around that problem. The best we can do is to allow 'expr_max' expressions (as in the binary syntax): binary_comprehension -> '<<' expr_max '||' lc_exprs '>>' : {bc,?anno('$1'),'$2','$4'}. That will work, but functions calls must be enclosed in parentheses: << (foo(X)) || X <- List >>
Diffstat (limited to 'lib/tools/test')
-rw-r--r--lib/tools/test/cover_SUITE.erl29
1 files changed, 21 insertions, 8 deletions
diff --git a/lib/tools/test/cover_SUITE.erl b/lib/tools/test/cover_SUITE.erl
index b9a9cd5be4..d4b346c407 100644
--- a/lib/tools/test/cover_SUITE.erl
+++ b/lib/tools/test/cover_SUITE.erl
@@ -29,7 +29,7 @@ all() ->
NoStartStop = [eif,otp_5305,otp_5418,otp_7095,otp_8273,
otp_8340,otp_8188,compile_beam_opts,eep37,
analyse_no_beam, line_0, compile_beam_no_file,
- otp_13277],
+ otp_13277, otp_13289],
StartStop = [start, compile, analyse, misc, stop,
distribution, reconnect, die_and_reconnect,
dont_reconnect_after_stop, stop_node_after_disconnect,
@@ -1253,7 +1253,7 @@ otp_8340(doc) ->
["OTP-8340. Bug."];
otp_8340(suite) -> [];
otp_8340(Config) when is_list(Config) ->
- ?line [{{t,1},1},{{t,4},1}] =
+ [{{t,1},1},{{t,2},1},{{t,4},1}] =
analyse_expr(<<"<< \n"
" <<3:2, \n"
" SeqId:62>> \n"
@@ -1547,10 +1547,8 @@ comprehension_8188(Cf) ->
" true]. \n" % 2
" two() -> 2">>, Cf), % 1
- %% The template cannot have a counter since it is not allowed to
- %% be a block.
?line [{{t,1},1},
- %% {{t,2},2},
+ {{t,2},2},
{{t,3},1},
{{t,4},1},
{{t,5},0},
@@ -1560,7 +1558,7 @@ comprehension_8188(Cf) ->
{{t,13},2},
{{t,14},2}] =
analyse_expr(<<"<< \n" % 1
- " << (X*2) >> || \n" % 2 (now: 0)
+ " << (X*2) >> || \n" % 2
" <<X>> <= << (case two() of\n"
" 2 -> 1;\n" % 1
" _ -> 2\n" % 0
@@ -1575,7 +1573,7 @@ comprehension_8188(Cf) ->
"two() -> 2">>, Cf),
?line [{{t,1},1},
- %% {{t,2},4},
+ {{t,2},4},
{{t,4},1},
{{t,6},1},
{{t,7},0},
@@ -1584,7 +1582,7 @@ comprehension_8188(Cf) ->
{{t,12},4},
{{t,13},1}] =
analyse_expr(<<"<< \n" % 1
- " << (2)\n" % 4 (now: 0)
+ " << (2)\n" % 4
" :(8) >> || \n"
" <<X>> <= << 1,\n" % 1
" (case two() of \n"
@@ -1766,6 +1764,21 @@ otp_13277(Config) ->
?line ok = file:delete(File),
ok.
+%% Test general expressions in a binary comprehension.
+otp_13289(Config) ->
+ Test = <<"-module(t).
+ -export([t/0]).
+
+ t() ->
+ << (id(<<I>>)) || I <- [1,2,3] >>.
+
+ id(I) -> I.
+ ">>,
+ File = cc_mod(t, Test, Config),
+ <<1,2,3>> = t:t(),
+ ok = file:delete(File),
+ ok.
+
%%--Auxiliary------------------------------------------------------------
analyse_expr(Expr, Config) ->