Scilab code-checking criteria

Checking id

function

valid name (00004)

Checks the name of functions:

• option: names may be tested against a given regexp pattern
• option: some minimal and maximal lengths of names may be defined.

Illegal calls (00035)

Checks that function calls are allowed: the list of concerned functions is configurable. Default = pause, abort, quit, exit

deprecated (00022)

Looks for calls to deprecated functions.

number of lines (00016)

Checks the number of lines inside a function body. Too many lines can decrease the readability. Default max lines number = 200.

number of return() (00040)

Checks that the number of calls to return in a function is less than a maximum. Default = only 1.

arguments

Unused input argument (00006)

Checks if a function's argument is useless or not. Useless arguments can decrease the readability.

Unassigned output argument (00007)

Checks if output arguments are defined before returning.

Space after separating commas (00029)

Checks that there is a space after each comma in the list of function arguments at call.

Duplicate argins or/and duplicate argouts (00005)

Checks if a function's argument (in/out) have no duplicate.

function y=foo(a, b, c, a) // probably an error
    ...
endfunction

function [y, a]=foo(a, b, c) // not necessarily an error but could be one
    ...
endfunction

Order of named inputs (00037)

Checks that named arguments are called at the right place.

function foo(a, b, c)
    ...
endfunction

function faa(x, y, z)
    foo(x, b = 1, z) // not ok
endfunction

function fee(x, y, z)
    foo(x, b = 1, c = 2) // ok
endfunction

function fii(x, y, z)
    foo(x, c = 2, b = 1) // not ok
endfunction

Operators, symbols, keywords

Bad use of ':' operator (00024)

Checks that in an implicit list a:b one or both bounds a or b is not another implicit list.

Deprecated @ (not) operator (00027)

Checks that the deprecated @ (not) operator is not used. ~ must now be used.

no NOT NOT (00034)

Checks that no double negation is used. Such expressions shall be simplified.

NOT EQUAL consistency (00041)

The 'not equal' operator can be written '~=', '@=' or '<>', so checks that only one is used.

== instead of = (00019)

Checks if the equality operator is used in a single instruction.

function y=foo(x)
    y == x + 1;     // probably a typo
endfunction

NaN comparisons (00018)

Most often, comparing a number with %nan isn't a good idea. Using isnan is better.

global keyword (00001)

Checks if the keyword global is present.

function y=foo(x)
    global z
endfunction

Redefinition of reserved keywords (00002)

Checks if a variable redefines a Scilab's constant, built-in or macro.

Redefining a Scilab's variable could have undesirable side-effects, so it should be avoided.

function y=foo(x)
    y = x
endfunction

function y=bar(x)
    y = foo(x)
endfunction

function y=oof(x)    // call oof(2) doesn't return 2 !
    foo = rand(x, 1);
    y = bar(x)
endfunction

TODO (00017)

Checks if there are comments including the TODO mnemonic. Most often, TODO points to something that still must be achieved.

Code style

Too long line (00015)

Checks the line length. Scilab code style recommends a 80-char maximal length. This is the default value for slint.

One instruction per line (00009)

Checks if there is a single instruction on each line.

Semicolon at end of line (00039)

Checks that lines end with a semicolon.

Binary operators between spaces (00028)

Checks that each binary operator (+ - * / > >= < <= = == .. is surrounded by spaces.

Format of literal decimal numbers (00013)

Checks if in a literal decimal number the correct exponent character is "e" or "E" (instead of "d" or "D"). In addition, checking that the decimal separator is a dot (instead of a comma) is also enabled by default.

Bracketed expressions (00033)

Checks that expressions are bracketed: that increases the code readability.

Comments: minimal required ratio wrt code (00036)

Computes and checks the ratio between number of lines and number of comments is greater than the minimum required. Default ratio = 30%.

McCabe complexity (00012)

Computes the simplified McCabe complexity of the code, and compares it to a reference.

Loops and blocks

Empty block (00010)

Checks if there are some empty blocks.

If or while tested conditions : max number of statements (00032)

Checks that the number of statements in the boolean condition is less than a maximum. Default = 5 max.

Nesting depth of blocks (00031)

Checks that the nesting depth of blocks is less than a maximum (default 3).

select (00023)

Checks select against various tests:

• A default else case is expected. Enabled by default.
• When there is only one case, select shall be replaced with a simpler if statement. Warning enabled by default.
• Empty case or else blocks are detected. Enabled by default.
• The homogeneity of tested values is checked: all case values must have the same type. Disabled by default.

unreachable code after return or break (00021)

Checks for unreachable code after a break or a return instruction. Unreachable code decreases code readability.

Loop: max number of break or continue (00030)

Check that numbers of break or continue in a loop are less than a maximum (default = only 1).

Miscellaneous

Implicit list a:b without %nan nor %inf bounds (00024)

Checks that an implicit list a:b is specified without any a or b bound set to %nan or %inf.

printf: number of data matches the format (00014)

In calls to printf(), checks when it's possible whether the number of % formating directives matches the number of provided data. The data types matching is not tested.

save/load with variables names (00026)

Checks that calls to load() and save() use the names of variables instead of variables handles.

struct: fields and data match (00025)

Checks the struct() definition:

• The numbers of fields names and values must match.
• option: field names may be tested against a given regexp pattern
• option: some minimal and maximal lengths of fields names may be defined.

; .

mopen/mclose pairs & mclose all (00011)

Checks when it's possible if the files opened with mopen() are closed with mclose(). Checks as well if mclose("all") is not used: it may have some side-effects.

Returned error flag must be tested (00038)

Checks that the error flag returned by some functions is actually retrieved and tested. The list of such functions is configurable.

function foo(a, b, c)
   [fd, err] = mopen(...) // ok err is returned
   if err ... then // ok err is checked
      ...
   end
   ...
   mclose(fd);
endfunction

Unassigned result. Useless operation (00020)

Checks if an operation without assignment is used in a single instruction.

function y=foo(x)
    x + 1;    // probably useless
endfunction

Variable: valid name (00003)

Checks if a variable's name matches a regex pattern. [some names yield an error and stop code-checking, like "3wrongName"]

Variable: missing usage or missing local definition (00003)

Looks for variables that are locally defined but unused. Such variables are useless and can decrease the code readability.

Looks for variables used without being locally defined. Values of such variables are silently heritated from the calling level. This may have side effects.

function y=foo(x)
    scilab = 123;
    y = bar(x);
endfunction

function y=bar(x)
    Scilab = 456;
    y = scilab + 1; // typo error
endfunction