Camel case and snake case: Difference between revisions
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(Python example) |
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" internal space " >camel " internalSpace " |
" internal space " >camel " internalSpace " |
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</pre> |
</pre> |
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=={{header|jq}}== |
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'''Adapted from [[#Wren|Wren]]''' |
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{{works with|jq}} |
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'''Works with gojq, the Go implementation of jq''' |
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'''Preliminaries''' |
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<lang jq>def isUpper: explode[0] | 65 <= . and . <= 90; |
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def lpad($len): tostring | ($len - length) as $l | (" " * $l)[:$l] + .; |
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# "White space is not permitted as part of camel case or snake case variable names." |
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def trim: sub("^\\s+";"") | sub("\\s+$";"");</lang> |
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'''Camel and Snake''' |
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<lang jq>def toCamel: |
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trim as $snake |
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| { camel: "", underscore : false} |
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| reduce ($snake|explode[]|[.]|implode) as $c (.; |
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if ["_", "-", " "]|index($c) |
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then .underscore = true |
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elif .underscore |
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then .camel += ($c|ascii_upcase) |
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| .underscore = false |
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else .camel += $c |
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end) |
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| .camel; |
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def toSnake: |
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(trim | gsub("\\s"; "_")) as $camel |
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| reduce ($camel|explode[1:][]|[.]|implode) as $c ( |
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$camel[0:1]; |
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if $c|isUpper |
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then ($c|ascii_downcase) as $lc |
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| if (.[-1:] | (. == "_" or . == "-")) |
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then . + $lc |
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else . + "_" + $lc |
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end |
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else . + $c |
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end ); |
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def tests: [ |
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"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis", |
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"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces " |
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]; |
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" === to_snake_case ===", |
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(tests[] | "\(lpad(33)) -> \(toSnake)"), |
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"", |
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" === toCamelCase ===", |
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(tests[] | "\(lpad(33)) -> \(toCamel)")</lang> |
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{{out}} |
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<pre> |
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=== to_snake_case === |
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snakeCase -> snake_case |
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snake_case -> snake_case |
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variable_10_case -> variable_10_case |
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variable10Case -> variable10_case |
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ɛrgo rE tHis -> ɛrgo_r_e_t_his |
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hurry-up-joe! -> hurry-up-joe! |
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c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc |
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spaces -> spaces |
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=== toCamelCase === |
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snakeCase -> snakeCase |
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snake_case -> snakeCase |
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variable_10_case -> variable10Case |
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variable10Case -> variable10Case |
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ɛrgo rE tHis -> ɛrgoRETHis |
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hurry-up-joe! -> hurryUpJoe! |
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c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc |
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spaces -> spaces |
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</pre> |
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=={{header|Julia}}== |
=={{header|Julia}}== |
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spaces => spaces |
spaces => spaces |
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</pre> |
</pre> |
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=={{header|Perl}}== |
=={{header|Perl}}== |
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Revision as of 07:23, 4 December 2021
Camel case and snake case is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Two common conventions for naming of computer program variables are Snake Case and Camel Case.
Snake case variables are generally all lower case, with an underscore between words in the variable, as in snake_case_variable'. Camel case variables are generally lower case first (except in some Pascal conventions or with class names in many other languages), with captalization of the initial letter of the words within the variable, as in 'camelCaseVariable'.
Leading underscores are not used in such variables except as part of a different naming convention, usually for special internal or system variables. White space is not permitted as part of camel case or snake case variable names.
- Task
- Write two functions, one to change snake case to camel case and one to change camel case to snake case. If possible, generalize the function enough to apply to strings containing spaces between words or a `-` dash between words, assuming that in those cases a space or hyphen is a also a separator character, like `_`, for the purpose of creating a new variable name. Leading or trailing whitespace may be ignored.
- Show the results on changing to both snake case and camel case for each of the following strings:
<lang java> "snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces " </lang>
- Related tasks
ALGOL 68
Treating space, - and _ as equivalent "break" characters (as in most of the other samples) and adding kebab case (as in the Raku sample) and resisting the urge to add "space case" for languages like Algol 68 where (insignificant) spaces can appear in identifiers... <lang algol68>BEGIN # convert camel case to and from snake case #
# returns c converted to uppercase if it is lowercase, c otherwise #
OP TOUPPER = ( CHAR c )STRING:
IF c >= "a" AND c <= "z" THEN REPR( ( ABS c - ABS "a" ) + ABS "A" ) ELSE c FI;
# returns c converted to lowercase if it is uppercase, c otherwise #
OP TOLOWER = ( CHAR c )STRING:
IF c >= "A" AND c <= "Z" THEN REPR( ( ABS c - ABS "A" ) + ABS "a" ) ELSE c FI;
# returns the camel case identifier c in snake case #
OP CAMELTOSNAKE = ( STRING c )STRING: c CAMELTOBREAK "_";
# returns the camel case identifier c in kebab case #
OP CAMELTOKEBAB = ( STRING c )STRING: c CAMELTOBREAK "-";
# returns TRUE if c is a "break" character ( " ", "-" or "_" ), FALSE otherwise #
OP ISBREAK = ( CHAR c )BOOL: c = " " OR c = "-" OR c = "_";
# returns the indentifier id (which is assumed to be in Camel case) #
# converted to snake or kebab case depending on break char #
PRIO CAMELTOBREAK = 9; # CAMELTOBREAK is dyadic so need a priority #
OP CAMELTOBREAK = ( STRING id, CHAR break char )STRING:
BEGIN
STRING result := "";
STRING orig = TRIM id; # remove leading and trailing spaces #
BOOL first := TRUE;
INT c pos := LWB orig;
WHILE c pos <= UPB orig DO
CHAR c = orig[ c pos ];
IF c >= "A" AND c <= "Z" THEN
# have an uppercase letter #
IF NOT first THEN result +:= break char FI;
result +:= TOLOWER c
ELIF ISBREAK c THEN
# replace one or more spaces and break characters by a single break #
BOOL have break := TRUE;
WHILE c pos <= UPB orig AND have break DO
IF have break := ISBREAK orig[ c pos ] THEN c pos +:= 1 FI
OD;
IF c pos <= UPB orig THEN
# the identifier didn't end wih a break #
result +:= break char + TOLOWER orig[ c pos ]
FI
ELSE
# lowercase or punctuation #
result +:= c
FI;
first := FALSE;
c pos +:= 1
OD;
result
END # CAMELTOBREAK # ;
# returns the identifier id ( which is assumed to be in snake/kebab/space case ) #
# converted to Camel case #
OP TOCAMEL = ( STRING id )STRING:
BEGIN
STRING result := "";
STRING orig = TRIM id; # remove leading and trailing spaces #
INT c pos := LWB orig;
WHILE c pos <= UPB orig DO
CHAR c = orig[ c pos ];
IF c >= "A" AND c <= "Z" THEN
# uppercase letter - leave as is #
result +:= c
ELIF NOT ISBREAK c THEN
# not a break - convert to lower case if necessary and move to the next #
result +:= TOLOWER c;
ELSE
# have a separator - skip all subsequent separators and upcase the follower #
BOOL have break := TRUE;
WHILE c pos <= UPB orig AND have break DO
IF have break := ISBREAK orig[ c pos ] THEN c pos +:= 1 FI
OD;
IF c pos <= UPB orig THEN
# the identifier didn't end with a break character #
result +:= TOUPPER orig[ c pos ]
FI
FI;
c pos +:= 1
OD;
result
END # TOCAMEL # ;
# returns s left-padded to len characters or s if s is already that long #
PRIO PAD = 9;
OP PAD = ( INT len, STRING s )STRING:
IF INT s len = ( UPB s - LWB s ) + 1;
s len >= len
THEN s
ELSE
STRING result := s;
FOR i FROM s len + 1 TO len DO " " +=: result OD;
result
FI # PAD # ;
# returns s with leading and trailing spaces removed #
OP TRIM = ( STRING s )STRING:
BEGIN
INT left := LWB s;
INT right := UPB s;
WHILE IF left > right THEN FALSE ELSE s[ left ] = " " FI DO left +:= 1 OD;
WHILE IF right < left THEN FALSE ELSE s[ right ] = " " FI DO right -:= 1 OD;
s[ left : right ]
END # TRIM # ;
# task test cases #
[]STRING identifier = ( "snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis"
, "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
);
print( ( "to snake case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", CAMELTOSNAKE identifier[ i ], newline ) )
OD;
print( ( "to Camel case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", TOCAMEL identifier[ i ], newline ) )
OD;
print( ( "to kebab case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", CAMELTOKEBAB identifier[ i ], newline ) )
OD
END</lang>
- Output:
to snake case:
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
╔ørgo rE tHis -> ╔ørgo_r_e_t_his
hurry-up-joe! -> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc
spaces -> spaces
to Camel case:
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
╔ørgo rE tHis -> ╔ørgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
to kebab case:
snakeCase -> snake-case
snake_case -> snake-case
variable_10_case -> variable-10-case
variable10Case -> variable10-case
╔ørgo rE tHis -> ╔ørgo-r-e-t-his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy-flag-day/12.doc
spaces -> spaces
Factor
In my interpretation of the task, leading/trailing whitespace should be ignored, not trimmed. And non-leading/trailing whitespace should be dealt with the same way as underscores and hyphens. Although the task says nothing about numbers, I chose to treat letter->number and number->letter transitions the same way as lower->upper for the sake of converting to snake case.
<lang factor>USING: formatting kernel math regexp sequences splitting splitting.extras unicode ;
! ignore leading/trailing whitespace
- preserve ( str quot -- newstr )
[ [ blank? ] split-head [ blank? ] split-tail swap ] dip call glue ; inline
- >snake ( str -- newstr )
[
R/ (\p{lower}\p{upper}|\d\p{alpha}|\p{alpha}\d)/
[ 1 short cut >lower "_" glue ] re-replace-with
R/ [\s-]/ "_" re-replace
] preserve ;
- capitalize ( str -- newstr ) 1 short cut swap >upper prepend ;
- >camel ( str -- newstr )
[
"\s_-" split harvest 1 short cut
[ capitalize ] map append "" join
] preserve ;
- test ( str -- )
dup >snake over dup >camel "%u >snake %u\n%u >camel %u\n" printf ;
{
"snakeCase" "snake_case" "variable_10_case" "variable10Case" "ɛrgo rE tHis" "hurry-up-joe!" "c://my-docs/happy_Flag-Day/12.doc" " spaces " " internal space "
} [ test ] each</lang>
- Output:
"snakeCase" >snake "snake_case" "snakeCase" >camel "snakeCase" "snake_case" >snake "snake_case" "snake_case" >camel "snakeCase" "variable_10_case" >snake "variable_10_case" "variable_10_case" >camel "variable10Case" "variable10Case" >snake "variable_10_case" "variable10Case" >camel "variable10Case" "ɛrgo rE tHis" >snake "ɛrgo_r_e_t_his" "ɛrgo rE tHis" >camel "ɛrgoRETHis" "hurry-up-joe!" >snake "hurry_up_joe!" "hurry-up-joe!" >camel "hurryUpJoe!" "c://my-docs/happy_Flag-Day/12.doc" >snake "c://my_docs/happy_Flag_Day/12.doc" "c://my-docs/happy_Flag-Day/12.doc" >camel "c://myDocs/happyFlagDay/12.doc" " spaces " >snake " spaces " " spaces " >camel " spaces " " internal space " >snake " internal_space " " internal space " >camel " internalSpace "
jq
Adapted from Wren
Works with gojq, the Go implementation of jq
Preliminaries <lang jq>def isUpper: explode[0] | 65 <= . and . <= 90;
def lpad($len): tostring | ($len - length) as $l | (" " * $l)[:$l] + .;
- "White space is not permitted as part of camel case or snake case variable names."
def trim: sub("^\\s+";"") | sub("\\s+$";"");</lang> Camel and Snake <lang jq>def toCamel:
trim as $snake
| { camel: "", underscore : false}
| reduce ($snake|explode[]|[.]|implode) as $c (.;
if ["_", "-", " "]|index($c)
then .underscore = true
elif .underscore
then .camel += ($c|ascii_upcase)
| .underscore = false
else .camel += $c
end)
| .camel;
def toSnake:
(trim | gsub("\\s"; "_")) as $camel
| reduce ($camel|explode[1:][]|[.]|implode) as $c (
$camel[0:1];
if $c|isUpper
then ($c|ascii_downcase) as $lc
| if (.[-1:] | (. == "_" or . == "-"))
then . + $lc
else . + "_" + $lc
end
else . + $c
end );
def tests: [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
];
" === to_snake_case ===", (tests[] | "\(lpad(33)) -> \(toSnake)"), "", " === toCamelCase ===", (tests[] | "\(lpad(33)) -> \(toCamel)")</lang>
- Output:
=== to_snake_case ===
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
ɛrgo rE tHis -> ɛrgo_r_e_t_his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc
spaces -> spaces
=== toCamelCase ===
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
ɛrgo rE tHis -> ɛrgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
Julia
<lang julia>#= Regex based variable name convention change string functions.
`sep` is the separator targeted for change from (to camel case) or to (to snake case) `allsep` is the separators other than `sep` that may be changed to `sep` `lcmiddle` is a boolean to set whether caps within camel case words are made lowercase
=#
function snakeToCamelCase(s; sep=r"[_]+", lcmiddle=false)
isempty(s) && return s words = split(strip(s), sep) return lowercasefirst(join(uppercasefirst.(lcmiddle ? lowercase.(words) : words)))
end
spaceToCamelCase(s) = snakeToCamelCase(s; sep=r"\s+") kebabToCamelCase(s) = snakeToCamelCase(s; sep=r"[\-]+") periodToCamelCase(s) = snakeToCamelCase(s; sep=r"[\.]+") allsepToCamelCase(s) = snakeToCamelCase(s; sep=r"[ \-_\.]+") lowermiddle_allsepToCamelCase(s) = snakeToCamelCase(s; sep=r"[ \-_\.]+", lcmiddle=true)
function camel_to_snake_case(s; sep="_", insep=sep, allsep=r"_+", lcmiddle=true)
s = isempty(s) ? (return s) : lowercasefirst(strip(s)) s = replace(s, r"[A-Z]+" => x -> sep * (lcmiddle ? lowercase(x) : lowercasefirst(x))) return replace(s, allsep => sep)
end
preserve_midcaps_camel_to_snake_case(s) = camel_to_snake_case(s; lcmiddle=false) allsep_to_snake_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+") allsep_to_kebab_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep="-") allsep_to_space_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep=" ") allsep_to_period_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep=".") allsep_to_slash_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep="/")
for f in [
snakeToCamelCase, spaceToCamelCase, kebabToCamelCase, periodToCamelCase, allsepToCamelCase, lowermiddle_allsepToCamelCase, camel_to_snake_case, preserve_midcaps_camel_to_snake_case, allsep_to_snake_case, allsep_to_kebab_case, allsep_to_space_case, allsep_to_period_case, allsep_to_slash_case,
]
println("Testing function $f:")
for teststring in [
"snakeCase",
"snake_case",
"snake-case",
"snake case",
"snake CASE",
"snake.case",
"variable_10_case",
"variable10Case",
"ɛrgo rE tHis",
"hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc",
" spaces ",
]
println(lpad(teststring, 36), " => ", f(teststring))
end
println()
end
</lang>
- Output:
Testing function snakeToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
Testing function spaceToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
Testing function kebabToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snakeCase
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
Testing function periodToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snakeCase
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12Doc
spaces => spaces
Testing function allsepToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function lowermiddle_allsepToCamelCase:
snakeCase => snakecase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCase
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10case
ɛrgo rE tHis => ɛrgoReThis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _case
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function preserve_midcaps_camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _cASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function allsep_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake_case
snake case => snake_case
snake CASE => snake_case
snake.case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo_r_e_t_his
hurry-up-joe! => hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc => c://my_docs/happy_flag_day/12_doc
spaces => spaces
Testing function allsep_to_kebab_case:
snakeCase => snake-case
snake_case => snake-case
snake-case => snake-case
snake case => snake-case
snake CASE => snake-case
snake.case => snake-case
variable_10_case => variable-10-case
variable10Case => variable10-case
ɛrgo rE tHis => ɛrgo-r-e-t-his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy-flag-day/12-doc
spaces => spaces
Testing function allsep_to_space_case:
snakeCase => snake case
snake_case => snake case
snake-case => snake case
snake case => snake case
snake CASE => snake case
snake.case => snake case
variable_10_case => variable 10 case
variable10Case => variable10 case
ɛrgo rE tHis => ɛrgo r e t his
hurry-up-joe! => hurry up joe!
c://my-docs/happy_Flag-Day/12.doc => c://my docs/happy flag day/12 doc
spaces => spaces
Testing function allsep_to_period_case:
snakeCase => snake.case
snake_case => snake.case
snake-case => snake.case
snake case => snake.case
snake CASE => snake.case
snake.case => snake.case
variable_10_case => variable.10.case
variable10Case => variable10.case
ɛrgo rE tHis => ɛrgo.r.e.t.his
hurry-up-joe! => hurry.up.joe!
c://my-docs/happy_Flag-Day/12.doc => c://my.docs/happy.flag.day/12.doc
spaces => spaces
Testing function allsep_to_slash_case:
snakeCase => snake/case
snake_case => snake/case
snake-case => snake/case
snake case => snake/case
snake CASE => snake//case
snake.case => snake/case
variable_10_case => variable/10/case
variable10Case => variable10/case
ɛrgo rE tHis => ɛrgo/r/e/t/his
hurry-up-joe! => hurry/up/joe!
c://my-docs/happy_Flag-Day/12.doc => c://my/docs/happy//flag//day/12/doc
spaces => spaces
Perl
<lang perl>#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Camel_case_and_snake_case use warnings;
my @words = (
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "#rgo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces " );
sub tosnake
{
shift =~ s/^ +| +$//gr =~ s/[A-Z]/_\l$&/gr =~ tr/ -/_/r =~ s/__+/_/gr;
}
sub tocamel
{
shift =~ s/^ +| +$//gr =~ s/[ _-]([a-z0-9])/\u$1/gir;
}
print "to snake case\n\n"; for my $word ( @words )
{
printf "%35s -> %s\n", $word, tosnake($word);
}
print "\nto camel case\n\n"; for my $word ( @words )
{
printf "%35s -> %s\n", $word, tocamel($word);
}</lang>
- Output:
to snake case
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
#rgo rE tHis -> #rgo_r_e_t_his
hurry-up-joe! -> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc
spaces -> spaces
to camel case
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
#rgo rE tHis -> #rgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
Phix
with javascript_semantics function to_snake_case(string s) string snake = substitute(trim(s)," ","_") for i=length(snake) to 1 by -1 do if isupper(snake[i]) then snake[i..i] = '_'&lower(snake[i]) end if end for return snake end function function toCamelCase(string s) string camel = substitute_all(trim(s),"- ","__") for i=length(camel)-1 to 1 by -1 do if camel[i]='_' then camel[i..i+1] = upper(camel[i+1..i+1]) end if end for return camel end function constant tests = {"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "} procedure test(string title, integer fn) printf(1,title) for i=1 to length(tests) do printf(1,"%33s ===> %s\n", {tests[i], fn(tests[i])}) end for end procedure test(" === to_snake_case ===\n",to_snake_case) test("\n === toCamelCase ===\n",toCamelCase)
- Output:
=== to_snake_case ===
snakeCase ===> snake_case
snake_case ===> snake_case
variable_10_case ===> variable_10_case
variable10Case ===> variable10_case
ergo rE tHis ===> ergo_r_e_t_his
hurry-up-joe! ===> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ===> c://my-docs/happy__flag-_day/12.doc
spaces ===> spaces
=== toCamelCase ===
snakeCase ===> snakeCase
snake_case ===> snakeCase
variable_10_case ===> variable10Case
variable10Case ===> variable10Case
ergo rE tHis ===> ergoRETHis
hurry-up-joe! ===> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc ===> c://myDocs/happyFlagDay/12.doc
spaces ===> spaces
Python
<lang python>""" https://rosettacode.org/wiki/Camel_case_and_snake_case """
import re
def snakeToCamelCase(nam, sep='[_]+', lcmiddle=False):
""" convert snake '_' separator case to camel case """
if nam == :
return nam
words = re.split(sep, nam.strip())
if lcmiddle:
words = [w.lower() for w in words]
words[1:] = [w[0].upper() + w[1:] for w in words[1:] if len(w) > 0]
return .join(words)
def spaceToCamelCase(nam):
""" convert space case to camel case """ return snakeToCamelCase(nam, sep='\s+')
def kebabToCamelCase(nam):
""" convert kebab '-' case to camel case """ return snakeToCamelCase(nam, sep='[\-]+')
def periodToCamelCase(nam):
""" convert period '.' case to camel case """ return snakeToCamelCase(nam, sep='[\.]+')
def allsepToCamelCase(nam):
""" convert all separators in allsep to camel case """ return snakeToCamelCase(nam, sep='[ \-_\.]+')
def lowermiddle_allsepToCamelCase(nam):
""" convert all separators to camel case, and all but word starts to lowercase """ return snakeToCamelCase(nam, sep='[ \-_\.]+', lcmiddle=True)
def camel_to_snake_case(nam, sep='_', allsep='[_]+', lcmiddle=True):
""" convert camel case to snake case (separate with '_') """
nam = re.sub('([A-Z]+)', sep + r"\1", nam.strip())
sep1 = '\\' + sep if sep == '.' else sep
if lcmiddle:
nam = sep.join([w.lower() for w in nam.split(sep1) if len(w) > 0])
else:
nam = sep.join([w[0].lower() + w[1:] for w in nam.split(sep1) if len(w) > 0])
return re.sub(allsep, sep, nam)
def preserve_midcaps_camel_to_snake_case(nam):
return camel_to_snake_case(nam, lcmiddle=False)
def allsep_to_snake_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+')
def allsep_to_kebab_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='-')
def allsep_to_space_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep=' ')
def allsep_to_period_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='.')
def allsep_to_slash_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='/')
for f in [
snakeToCamelCase,
spaceToCamelCase,
kebabToCamelCase,
periodToCamelCase,
allsepToCamelCase,
lowermiddle_allsepToCamelCase,
camel_to_snake_case,
preserve_midcaps_camel_to_snake_case,
allsep_to_snake_case,
allsep_to_kebab_case,
allsep_to_space_case,
allsep_to_period_case,
allsep_to_slash_case]:
print(f"Testing function {f}:")
for teststring in [
"snakeCase",
"snake_case",
"snake-case",
"snake case",
"snake CASE",
"snake.case",
"variable_10_case",
"variable10Case",
"ɛrgo rE tHis",
"hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc",
" spaces "]:
print(teststring.rjust(36), " => ", f(teststring))
print()
</lang>
- Output:
Testing function <function snakeToCamelCase at 0x000001F17C25AC10>:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
Testing function <function spaceToCamelCase at 0x000001F17C25AA60>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
Testing function <function kebabToCamelCase at 0x000001F17C25ADC0>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snakeCase
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
Testing function <function periodToCamelCase at 0x000001F17C25AE50>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snakeCase
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12Doc
spaces => spaces
Testing function <function allsepToCamelCase at 0x000001F17C25AEE0>:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function <function lowermiddle_allsepToCamelCase at 0x000001F17C25AF70>:
snakeCase => snakecase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCase
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10case
ɛrgo rE tHis => ɛrgoReThis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function <function camel_to_snake_case at 0x000001F17C262040>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _case
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function <function preserve_midcaps_camel_to_snake_case at 0x000001F17C2620D0>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _cASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function <function allsep_to_snake_case at 0x000001F17C262160>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake_case
snake case => snake_case
snake CASE => snake_case
snake.case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo_r_e_t_his
hurry-up-joe! => hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc => c://my_docs/happy_flag_day/12_doc
spaces => spaces
Testing function <function allsep_to_kebab_case at 0x000001F17C2621F0>:
snakeCase => snake-case
snake_case => snake-case
snake-case => snake-case
snake case => snake-case
snake CASE => snake-case
snake.case => snake-case
variable_10_case => variable-10-case
variable10Case => variable10-case
ɛrgo rE tHis => ɛrgo-r-e-t-his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy-flag-day/12-doc
spaces => spaces
Testing function <function allsep_to_space_case at 0x000001F17C262280>:
snakeCase => snake case
snake_case => snake case
snake-case => snake case
snake case => snake case
snake CASE => snake case
snake.case => snake case
variable_10_case => variable 10 case
variable10Case => variable10 case
ɛrgo rE tHis => ɛrgo r e t his
hurry-up-joe! => hurry up joe!
c://my-docs/happy_Flag-Day/12.doc => c://my docs/happy flag day/12 doc
spaces => spaces
Testing function <function allsep_to_period_case at 0x000001F17C262310>:
snakeCase => snake.case
snake_case => snake.case
snake-case => snake.case
snake case => snake.case
snake CASE => snake.case
snake.case => snake.case
variable_10_case => variable.10.case
variable10Case => variable10.case
ɛrgo rE tHis => ɛrgo.r.e.t.his
hurry-up-joe! => hurry.up.joe!
c://my-docs/happy_Flag-Day/12.doc => c://my.docs/happy.flag.day/12.doc
spaces => spaces
Testing function <function allsep_to_slash_case at 0x000001F17C2623A0>:
snakeCase => snake/case
snake_case => snake/case
snake-case => snake/case
snake case => snake/case
snake CASE => snake//case
snake.case => snake/case
variable_10_case => variable/10/case
variable10Case => variable10/case
ɛrgo rE tHis => ɛrgo/r/e/t/his
hurry-up-joe! => hurry/up/joe!
c://my-docs/happy_Flag-Day/12.doc => c:/my/docs/happy//flag//day/12/doc
spaces => spaces
Raku
The specs are a little vague, but taking a wild stab at it... (May be completely wrong but without any examples of expected output it is hard to judge. This is what I would expect at least...)
<lang perl6>my @tests = qww<
snakeCase snake_case variable_10_case variable10Case "ɛrgo rE tHis" hurry-up-joe! c://my-docs/happy_Flag-Day/12.doc " spaces "
>;
sub to_snake_case (Str $snake_case_string is copy) {
$snake_case_string.=trim;
return $snake_case_string if $snake_case_string.contains: / \s | '/' /;
$snake_case_string.=subst: / <after <:Ll>> (<:Lu>|<:digit>+) /, {'_' ~ $0.lc}, :g;
$snake_case_string.=subst: / <after <:digit>> (<:Lu>) /, {'_' ~ $0.lc}, :g;
}
sub toCamelCase (Str $CamelCaseString is copy) {
$CamelCaseString.=trim;
return $CamelCaseString if $CamelCaseString.contains: / \s | '/' /;
$CamelCaseString.=subst: / ('_') (\w) /, {$1.uc}, :g;
}
sub to-kebab-case (Str $kebab-case-string is copy) {
$kebab-case-string.=trim;
return $kebab-case-string if $kebab-case-string.contains: / \s | '/' /;
$kebab-case-string.=subst: / ('_') (\w) /, {'-' ~ $1.lc}, :g;
$kebab-case-string.=subst: / <after <:Ll>> (<:Lu>|<:digit>+) /, {'-' ~ $0.lc}, :g;
$kebab-case-string.=subst: / <after <:digit>> (<:Lu>) /, {'-' ~ $0.lc}, :g;
}
say "{' ' x 30}to_snake_case"; printf "%33s ==> %s\n", $_, .&to_snake_case for @tests; say "\n{' ' x 30}toCamelCase"; printf "%33s ==> %s\n", $_, .&toCamelCase for @tests; say "\n{' ' x 30}to-kabab-case"; printf "%33s ==> %s\n", $_, .&to-kebab-case for @tests;</lang>
- Output:
to_snake_case
snakeCase ==> snake_case
snake_case ==> snake_case
variable_10_case ==> variable_10_case
variable10Case ==> variable_10_case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
toCamelCase
snakeCase ==> snakeCase
snake_case ==> snakeCase
variable_10_case ==> variable10Case
variable10Case ==> variable10Case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
to-kabab-case
snakeCase ==> snake-case
snake_case ==> snake-case
variable_10_case ==> variable-10-case
variable10Case ==> variable-10-case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
Wren
Well, I'm not entirely sure what I'm doing here as a result of space and hyphen being treated as equivalent to underscore but, in the case of the 'to snake' conversion:
1. I've retained any hyphens in the result string but replaced spaces with underscores as it says that white space is not permitted as part of the variable name.
2. I've assumed that an underscore should not be added if the previous character was already a separator. <lang ecmascript>import "./str" for Char import "/fmt" for Fmt
var toCamel = Fn.new { |snake|
snake = snake.trim()
var camel = ""
var underscore = false
for (c in snake) {
if ("_- ".contains(c)) {
underscore = true
} else if (underscore) {
camel = camel + Char.upper(c)
underscore = false
} else {
camel = camel + c
}
}
return camel
}
var toSnake = Fn.new { |camel|
camel = camel.trim().replace(" ", "_") // we don't want any spaces in the result
var snake = ""
var first = true
for (c in camel) {
if (first) {
snake = snake + c
first = false
} else if (!first && Char.isUpper(c)) {
if (snake[-1] == "_" || snake[-1] == "-") {
snake = snake + Char.lower(c)
} else {
snake = snake + "_" + Char.lower(c)
}
} else {
snake = snake + c
}
}
return snake
}
var tests = [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
]
System.print(" === to_snake_case ===") for (camel in tests) {
Fmt.print("$33s -> $s", camel, toSnake.call(camel))
}
System.print("\n === toCamelCase ===") for (snake in tests) {
Fmt.print("$33s -> $s", snake, toCamel.call(snake))
}</lang>
- Output:
=== to_snake_case ===
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
ɛrgo rE tHis -> ɛrgo_r_e_t_his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc
spaces -> spaces
=== toCamelCase ===
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
ɛrgo rE tHis -> ɛrgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
XPL0
<lang XPL0>string 0; \use zero-terminated strings char Out(100); \output string (made global for safety)
func Trim(Str); \Trim leading and trailing spaces from string char Str; int I; [while Str(0) = $20 do Str:= Str+1; \skip leading spaces I:= 0; \skip to end of string (+1) while Str(I) # 0 do I:= I+1; while I>0 & Str(I-1)=$20 do I:= I-1; \skip back to first non-space Str(I):= 0; \chop off any trailing spaces return Str; ];
func ToSnake(In); \Convert string to snake_case char In; int I, J, C, UL; [I:= 0; J:= 0; UL:= true; \suppress leading & redundant underlines repeat C:= In(I); I:= I+1; \get character from input string
if C>=^A & C<=^Z then \convert uppercase to "_" + lowercase
[if not UL then [Out(J):= ^_; J:= J+1];
Out(J):= C+$20; J:= J+1;
UL:= false;
]
else if C=$20 or C=^- then \convert to underlines
[if not UL then [Out(J):= ^_; J:= J+1; UL:= true]
]
else [Out(J):= C; J:= J+1; UL:= C=^_];
until C = 0; return Out; ];
func ToCamel(In); \Convert string to camelCase char In; int I, J, C; [I:= 0; J:= 0; repeat C:= In(I); I:= I+1;
if C=^_ or C=^- or C=$20 then
[C:= In(I); I:= I+1;
if C>=^a & C<=^z then C:= C-$20;
Out(J):= C; J:= J+1;
]
else [Out(J):= C; J:= J+1];
until C = 0; return Out; ];
int Strings, I; [Strings:= [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "\u025brgo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "];
Text(0, "To snake case:^M^J"); for I:= 0 to 7 do
[Text(0, Strings(I)); Text(0, " -> "); Text(0, ToSnake(Trim(Strings(I)))); CrLf(0); ];
Text(0, "To camel case:^M^J"); for I:= 0 to 7 do
[Text(0, Strings(I)); Text(0, " -> "); Text(0, ToCamel(Trim(Strings(I)))); CrLf(0); ];
]</lang>
- Output:
To snake case: snakeCase -> snake_case snake_case -> snake_case variable_10_case -> variable_10_case variable10Case -> variable10_case \u025brgo rE tHis -> \u025brgo_r_e_t_his hurry-up-joe! -> hurry_up_joe! c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc spaces -> spaces To camel case: snakeCase -> snakeCase snake_case -> snakeCase variable_10_case -> variable10Case variable10Case -> variable10Case \u025brgo rE tHis -> \u025brgoRETHis hurry-up-joe! -> hurryUpJoe! c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc spaces -> spaces