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POTTIER Francois
menhir
Commits
68b4af50
Commit
68b4af50
authored
Jul 06, 2015
by
POTTIER Francois
Browse files
More cleanup.
parent
e7fafc9d
Changes
1
Hide whitespace changes
Inline
Sidebyside
src/Coverage.ml
View file @
68b4af50
...
...
@@ 132,11 +132,10 @@ let causes_an_error s z =
would be faster, but (according to a quick experiment) the paths thus
obtained would be really far from optimal. *)
module
P
=
CompletedNatWitness
type
property
=
Terminal
.
t
P
.
t
module
P
=
struct
include
CompletedNatWitness
type
property
=
Terminal
.
t
t
end
(*  *)
...
...
@@ 146,7 +145,7 @@ type property =
If so, [s'] is passed to the continuation [k]. Otherwise, [P.bottom] is
returned. *)
let
has_transition
s
sym
k
:
property
=
let
has_transition
s
sym
k
:
P
.
property
=
try
let
s'
=
SymbolMap
.
find
sym
(
Lr1
.
transitions
s
)
in
k
s'
...
...
@@ 155,7 +154,7 @@ let has_transition s sym k : property =
(* This computes a minimum over a set of terminal symbols. *)
let
foreach_terminal_in
toks
(
f
:
Terminal
.
t
>
property
)
:
property
=
let
foreach_terminal_in
toks
(
f
:
Terminal
.
t
>
P
.
property
)
:
P
.
property
=
TerminalSet
.
fold
(
fun
t
accu
>
(* Using [min_lazy] allows stopping if we find a path of length 0.
This is just an optimization. *)
...
...
@@ 165,7 +164,7 @@ let foreach_terminal_in toks (f : Terminal.t > property) : property =
(* This is analogous to [foreach_terminal_in], but stops as soon as a
finite value is reached, i.e., as soon as one path is found. *)
let
foreach_terminal_until_finite
(
f
:
Terminal
.
t
>
property
)
:
property
=
let
foreach_terminal_until_finite
(
f
:
Terminal
.
t
>
P
.
property
)
:
P
.
property
=
Terminal
.
fold
(
fun
t
accu
>
(* We stop as soon as we obtain a finite result. *)
P
.
until_finite
accu
(
fun
()
>
f
t
)
...
...
@@ 173,7 +172,7 @@ let foreach_terminal_until_finite (f : Terminal.t > property) : property =
(* This computes a minimum over the productions associated with [nt]. *)
let
foreach_production
nt
(
f
:
Production
.
index
>
property
)
:
property
=
let
foreach_production
nt
(
f
:
Production
.
index
>
P
.
property
)
:
P
.
property
=
Production
.
foldnt
nt
P
.
bottom
(
fun
prod
accu
>
(* Using [min_lazy] allows stopping if we find a path of length 0.
This is just an optimization. *)
...
...
@@ 256,12 +255,15 @@ module QuestionMap =
let
first
=
Analysis
.
first_prod_lookahead
(* The following function answers a question. This requires a fixed point
computation. We have a certain amount of flexibility in how much
information we memoize; if we use a recursive call to [answer], we
recompute; if we use a call to [get], we memoize. *)
(* The following function defines the analysis. *)
(* We have a certain amount of flexibility in how much information we memoize;
if we use a recursive call to [answer], we recompute; if we use a call to
[get], we memoize. As long as every direct recursive call is decreasing,
either choice is acceptable. A quick experiment suggests that memoization
everywhere is costeffective. *)
let
answer
(
q
:
question
)
(
get
:
question
>
property
)
:
property
=
let
answer
(
q
:
question
)
(
get
:
question
>
P
.
property
)
:
P
.
property
=
let
rhs
=
Production
.
rhs
q
.
prod
in
let
n
=
Array
.
length
rhs
in
...
...
@@ 297,12 +299,11 @@ let answer (q : question) (get : question > property) : property =
match
sym
with

Symbol
.
T
t
>
(* Case 2a. [sym] is a terminal symbol [t]. Our precondition
implies that [t] is equal to [a]. [w] must begin with [a]
The rest must be some word [w'] such that, by starting from
[s'] and by reading [w'], we reach our goal. The first letter
in [w'] could be any terminal symbol [c], so we try all of
them. *)
(* Case 2a. [sym] is a terminal symbol [t]. Our precondition implies
that [t] is equal to [a]. [w] must begin with [a]. The rest must
be some word [w'] such that, by starting from [s'] and by reading
[w'], we reach our goal. The first letter in [w'] could be any
terminal symbol [c], so we try all of them. *)
assert
(
Terminal
.
equal
q
.
a
t
);
(* per our precondition *)
P
.
add
(
P
.
singleton
q
.
a
)
(
...
...
@@ 314,11 +315,11 @@ let answer (q : question) (get : question > property) : property =

Symbol
.
N
nt
>
(* Case 2b. [sym] is a nonterminal symbol [nt]. For each letter [c],
for each production [prod'] associated with [nt], we
must
concatenate:
1 a word that takes us from [s], beginning with [a],
to a state
where we can reduce [prod'], looking at [c];
and 2 a
word that takes us from [s'], beginning with [c], to a state
where
we reach our original goal. *)
for each production [prod'] associated with [nt], we
concatenate:
1 a word that takes us from [s], beginning with [a],
to a state
where we can reduce [prod'], looking at [c];
2 a
word that takes us from [s'], beginning with [c], to a state
where
we reach our original goal. *)
foreach_terminal_in
(
first
q
.
prod
(
q
.
i
+
1
)
q
.
z
)
(
fun
c
>
foreach_production
nt
(
fun
prod'
>
...
...
@@ 335,7 +336,7 @@ let answer (q : question) (get : question > property) : property =
end
(* Debugging
wrapper
. TEMPORARY *)
(* Debugging. TEMPORARY *)
let
qs
=
ref
0
let
answer
q
get
=
incr
qs
;
...
...
@@ 343,21 +344,33 @@ let answer q get =
Printf
.
fprintf
stderr
"qs = %d
\n
%!"
!
qs
;
answer
q
get
(* The fixed point. *)
module
F
=
Fix
.
Make
(
Maps
.
PersistentMapsToImperativeMaps
(
QuestionMap
))
(
struct
include
P
type
property
=
Terminal
.
t
t
end
)
(
P
)
let
answer
:
question
>
property
=
let
answer
:
question
>
P
.
property
=
F
.
lfp
answer
(*  *)
(* We now wish to determine, given a state [s'] and a terminal symbol [z],
a minimal path that takes us from some entry state to state [s'] with
[z] as the next (unconsumed) symbol. *)
(* This can be formulated as a search for a shortest path in a graph. The
graph is not just the automaton, though. It is a (much) larger graph
whose vertices are pairs [s, z] and whose edges are obtained by calling
the expensive analysis above. Because we perform a backward search, from
[s', z] to any entry state, we use reverse edges, from a state to its
predecessors in the automaton. *)
(* Debugging. TEMPORARY *)
let
es
=
ref
0
exception
Success
of
property
let
backward
(
s'
,
z
)
:
property
=
let
backward
(
s'
,
z
)
:
P
.
property
=
let
module
G
=
struct
type
vertex
=
Lr1
.
node
*
Terminal
.
t
let
equal
(
s'1
,
z1
)
(
s'2
,
z2
)
=
...
...
@@ 389,6 +402,7 @@ let backward (s', z) : property =
)
(
Lr1
.
predecessors
s'
)
end
in
let
module
D
=
Dijkstra
.
Make
(
G
)
in
let
module
S
=
struct
exception
Success
of
P
.
property
end
in
try
let
_
=
D
.
search
(
fun
(
distance
,
(
v'
,
_
)
,
path
)
>
incr
es
;
...
...
@@ 396,13 +410,13 @@ let backward (s', z) : property =
Printf
.
fprintf
stderr
"es = %d
\n
%!"
!
es
;
if
Lr1
.
incoming_symbol
v'
=
None
then
let
path
=
List
.
map
snd
path
in
raise
(
Success
(
P
.
Finite
(
distance
,
Seq
.
concat
path
)))
(* TEMPORARY keep path *)
raise
(
S
.
Success
(
P
.
Finite
(
distance
,
Seq
.
concat
path
)))
(* TEMPORARY keep path *)
)
in
P
.
bottom
with
Success
p
>
with
S
.
Success
p
>
p
let
backward
s'
:
property
=
let
backward
s'
:
P
.
property
=
Printf
.
fprintf
stderr
"Attempting to reach an error in state %d:
\n
%!"
...
...
@@ 444,3 +458,4 @@ let () =
(* TEMPORARY avoid [error] token unless forced to use it *)
(* TEMPORARY implement and exploit [Lr1.ImperativeNodeMap] using an array *)
(* TEMPORARY the code in this module should run only if coverage is set *)
(* TEMPORARY gain a constant factor by memoizing [nullable_first_prod]? *)
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