The `lpsactionrename`

tool renames actions in an LPS, based on their names and
on the data parameters they carry. The tool can be used in two ways: either by
supplying it with a rename file or by providing a regular expression. A rename
file is provided using the option `--renamefile`

and a regular expression can
be specified with the option `--regex`

. Both modes are explained below.

ActionRenameRuleRHS ActionRenameRule ActionRenameRuleSpec ActionRenameSpec

ActionRenameRuleRHS::=`Action`

| 'tau' | 'delta'ActionRenameRule::= (`DataExpr`

'->' ) ?`Action`

'=>'`ActionRenameRuleRHS`

';'ActionRenameRuleSpec::=`VarSpec`

? 'rename'`ActionRenameRule`

+ActionRenameSpec::= (`SortSpec`

|`ConsSpec`

|`MapSpec`

|`EqnSpec`

|`ActSpec`

|`ActionRenameRuleSpec`

) +

The format of the RENAMEFILE can contain `sort`

, `cons`

, `map`

, `eqn`

and `act`

sections as in a mcrl2 file. This is followed by a `rename`

section to define the rename rules. The sections `sort`

, `cons`

, `map`

,
`eqn`

and `act`

are meant for new declarations that will be added to the LPS
and can be used in the rename rules. The new declarations are not allowed to
contain any conflicts with the declarations of the LPS. The `rename`

section
can be preceded by a `var`

section, where variables can be declared for the
rename rules.

The rename rules have the format: `rename c -> a1 => a2;`

where `c`

is a
boolean expression that has to hold to rename an occurrence of `a1`

into
`a2`

. The condition can be left out, in which case it is interpreted as
`true`

(*i.e.*, all occurrences of `a1`

will be renamed). The action `a1`

can contain arguments that can either be uniquely occurring variables or closed
terms. The arguments of `a2`

can be arbitrary terms, but the variables
occurring in it must also occur in `a1`

. The condition is an expression of
sort `Bool`

and can also only use variables that also occur in `a1`

.

It is possible use `tau`

for `a2`

; note that this means that a
multi-action of the form `a1|b`

will be replaced by `b`

. Instead of an
action, `a2`

may also be `delta`

. In this case, the action and the following
process call are replaced by `delta`

.

The renaming rules are applied from top to bottom to an linear process equation. If no value for the variables in a rename rule can be found to match an action, the next rule is applied. If no rule applies the action is left untouched. Variables in different rename rules with the same variable names are independent when being matched.

After the LPS has been renamed, sum elimination and rewriting will be applied to simplify the result. This can be skipped using appropriate switches.

Upon loading the rename file, `lpsactionrename`

will check if the following
conditions hold:

- Variables used in the condition or in the right side of a rename rule must also occur in the left side of that rename rule.
- All arguments of the action at the left hand side must either be closed terms or variables. Each variable can only occur once in the left hand side.
- All used actions and data types must be declared in the LPS file or locally.
- All conditions are data expressions of sort
`Bool`

. - All elements are well typed with respect to the declarations in the LPS or the rename file.

Consider an LPS with the process specification:

```
P(x:Bool) = sum y:Nat. (y < 6) -> a(x,y). P(!x);
```

and a rename file with the following rename rules:

```
act b: Bool;
var v: Nat; w:Bool;
rename
w -> a(w,v) => b(v==5);
(v==v*2)==w -> a(w,v) => tau;
a(w,5) => delta;
```

The arguments of an action do not have to consist of a single variable, as is
done in the second rename rule. In the second rename rule, `a(w,2*v)`

, `w`

and `2*v`

will be respectively equal to `x`

and `y`

from the LPS action
`a(x,y)`

.

The result of applying the rename rules to the LPS without sum elimination will give:

```
proc P(x_P0: Bool) =
true ->
delta
+ sum w: Bool,v,y_P0: Nat.
((y_P0 < 6 && w==x_P0 && v==y_P0) && w) -> b(v==5).P(!x_P0);
+ sum w00: Bool,v00: Nat,w: Bool,v,y_P0: Nat.
((((y_P0 < 6 && w==x_P0 && v==y_P0) && !w) && w00==x_P0 && v00==y_P0) &&
(v00==v00*2)==w00) -> tau.P(!x_P0)
+ sum w01,w00: Bool,v00: Nat,w: Bool,v,y_P0: Nat.
((((((y_P0 < 6 && w==x_P0 && v==y_P0) && !w) && w00==x_P0 && v00==y_P0) &&
!((v00==v00*2)==w00)) && w01==x_P0) && 5==y_P0) -> delta
+ sum w01,w00: Bool,v00: Nat,w: Bool,v,y_P0: Nat.
((((((y_P0 < 6 && w==x_P0 && v==y_P0) && !w) && w00==x_P0 && v00==y_P0) &&
!((v00==v00*2)==w00)) && w01==x_P0) && !(5==y_P0)) -> a(x_P0, y_P0).P(!x_P0)
```

Most of the introduced sum variables have a single point domain, namely: `u`

,
`w`

, `w_S00`

, `w_s01`

, `v_S00`

and in the last two summands, `y`

.
These variables can be eliminated by applying sum elimination. For example: in
the first summand `w`

is equal to `x`

. Therefore `w`

can be substituted by
`x`

, and `w`

can then be removed from the sum since it is no longer used.

Applying sum elimination will give the following result:

```
proc P(x_P0: Bool) =
true -> delta
+ sum y_P0: Nat.(y_P0 < 6 && x_P0) ->b(y_P0 == 5) .P(!x_P0);
+ sum y_P0: Nat.(y_P0 < 6 && !(y_P0 == y_P0 * 2)) ->tau.P(!(y_P0 == y_P0 * 2))
+ (!x_P0 && x_P0) ->delta
+ sum y_P0: Nat.(((y_P0 < 6 && !x_P0) && !((y_P0 == y_P0 * 2) == x_P0)) &&
!(5 == y_P0)) -> a(x_P0, y_P0) .P(!x_P0)
```

A regular expression has to be provided in the shape `matching pattern/replacement`

.
The replacement pattern follows the standard of ECMAScript. Groups matched with
parentheses can be substituted in the replacement string using `$n`

, where
`n`

is the index of the matched group. See the
ECMAScript website
for more details.

We consider the following process:

```
proc P(s1: Pos) =
(s1 == 3) ->
a_out|c_out .
P(s1 = 2)
+ (s1 == 2) ->
b_out .
P(s1 = 1)
+ (s1 == 1) ->
c_out .
P(s1 = 4)
+ (s1 == 4) ->
delta;
```

We can remove the prefix of `a_out`

and `c_out`

using the regular expression
`^([^b])_out$/$1`

. It is generally a good idea to write regular expressions in
the shape `^expression$`

to ensure the whole action name is matched.

It is also possible to rename actions to delta or to tau. For example, when
renaming `a_out`

to `delta`

using `^a_out$/delta`

, the multi action
`a_out|c_out`

will become `delta`

.

```
lpsactionrename [OPTION]... (--renamefile=NAME | --regex=EXPR) [INFILE [OUTFILE]]
```

Apply the action rename specification in FILE to the LPS in INFILE and save it to OUTFILE. If OUTFILE is not present, stdout is used. If INFILE is not present, stdin is used.

`-o`

, `--no-rewrite`

do not rewrite data expressions while renaming; use when the rewrite system does not terminate

`-m`

, `--no-sumelm`

do not apply sum elimination to the final result

`-t`

, `--no-typecheck`

do not typecheck the resulting specfication

`-QNUM`

, `--qlimitNUM`

limit enumeration of quantifiers to NUM variables. (Default NUM=1000, NUM=0 for unlimited).

`-eEXPR`

, `--regexEXPR`

use the provided regular expression to rename action labels. Argument should be of the shape ‘matching pattern/replacement’. Matched groups can be substituted in the result with $n, where n is the index of the group. It is generally good to surround the matching expression with ^$. Example: ‘^(.*)_send$/$1_receive’

`-fNAME`

, `--renamefileNAME`

use the rename rules from NAME

`-rNAME`

, `--rewriterNAME`

use rewrite strategy NAME:

`jitty`

jitty rewriting

`jittyc`

compiled jitty rewriting

`jittyp`

jitty rewriting with prover

`--timings[FILE]`

append timing measurements to FILE. Measurements are written to standard error if no FILE is provided

`-q`

, `--quiet`

do not display warning messages

`-v`

, `--verbose`

display short intermediate messages

`-d`

, `--debug`

display detailed intermediate messages

`--log-levelLEVEL`

display intermediate messages up to and including level

`-h`

, `--help`

display help information

`--version`

display version information

Jan Friso Groote and Tom Haenen