Parsing JSON in ARexx

[_amiga_]

Hi!

Given this example JSON object: { "firstName": "John", "lastName": "Doe", "email": "john.doe@example.com", "age": 45, "weight": 67, "admin": true }

how do I parse it in ARexx ?


... and this one (more complex):

{ "name": "Jason Ray", "profession": "Software Engineer", "age": 31, "address": { "city": "New York", "postalCode": 64780, "Country": "USA" }, "languages": ["Java", "Node.js", "JavaScript", "JSON"], "socialProfiles": [ { "name": "Twitter", "link": "https://twitter.com" }, { "name": "Facebook", "link": "https://www.facebook.com" } ] }


Thanks!

[daxb]

Maybe this is helpful: https://wiki.amigaos.net/wiki/AmigaO..._ARexx_Parsing

[Karlos]

This is an interesting one because IIRC Rexx uses a variable structure not unlike JS.

[daxb]

Parsing by pattern:

/**/

object='"firstName": "John", "lastName": "Doe", "email": "john.doe@example.com", "age": 45, "weight": 67, "admin": true'

PARSE VAR object '"firstName":' fN ',' '"lastName":' lN ',' '"email":' email ',' '"age":' age ',' '"weight":' weight ',' 'admin":' admin

SAY fN lN email age weight admin

Maybe there is another/better way? The complex example need other techniques.

[_amiga_]

I've found this Rexx code for parsing JSON.
It's for os/2, can somebody adapt it to work in ARexx ?


/*
* Filename: JSon2Rx.cmd
* Author: Jan-Erik
* Created: Sat Feb 23 2013
* Purpose: Interpret a JSon-file and place in stem
* Changes:
*/

IF ARG() > 0 THEN
IF STREAM( ARG(1), 'C', 'QUERY EXISTS' ) <> '' THEN
f_name = ARG(1)
ELSE
f_name = 'london.json'
ELSE
f_name = 'london.json'

IF STREAM( f_name, 'C', 'QUERY EXISTS' ) = '' THEN RETURN 1
f_size = STREAM( f_name, 'C', 'QUERY SIZE' )
f_input = CHARIN( f_name, 1, f_size )
CALL STREAM f_name, 'C', 'CLOSE'

stem = 'json.'
DO WHILE fromJSon( f_input ) > 0
CALL CHAROUT 'STDERR', 'Parts of the file missing! Press Enter to read it again. '
PARSE PULL
f_size = STREAM( f_name, 'C', 'QUERY SIZE' )
f_input = CHARIN( f_name, 1, f_size )
CALL STREAM f_name, 'C', 'CLOSE'
END

DO i = 1 TO json.0
SAY json.i '=' VALUE( json.i )
END

RETURN 0

fromJSon: PROCEDURE EXPOSE (stem)
!_str_json_! = ARG(1)
!_stem_counter_! = 0
!_not_in_key_range_! = SPACE( TRANSLATE( XRANGE(),, XRANGE( 'a', 'z' )||XRANGE( 'A', 'Z' )||XRANGE( 0, 9 )||'_' ), 0 )
IF SYMBOL( stem ) <> 'LIT' THEN
stem = 'STEM'
stem = STRIP( TRANSLATE( stem ), 'T', '.' )
!_s_name_! = stem
DO WHILE LENGTH( !_str_json_! ) > 0
PARSE VALUE !_str_json_! WITH !_key_!':'!_str_json_!
IF POS( '{', STRIP( !_key_! ) ) = 1 THEN
DO
PARSE VALUE !_key_! WITH '{'!_key_!
!_key_! = SPACE( TRANSLATE( !_key_!,, !_not_in_key_range_! ), 0 )
END
CALL calc4Pos
IF !_strt_brkt_! < !_key_val_del_! & !_strt_brkt_! < !_end_brkt_! & 0 < !_strt_brkt_! THEN
DO
PARSE VALUE !_str_json_! WITH '{'!_str_json_!
!_key_! = SPACE( TRANSLATE( !_key_!,, !_not_in_key_range_! ), 0 )
IF !_strt_sqr_brkt_! < !_strt_brkt_! & 0 < !_strt_sqr_brkt_! THEN
DO
!_s_name_! = !_s_name_!'.'TRANSLATE( !_key_! )'.0'
IF POS( '.', !_s_name_! ) > 0 THEN
DO
PARSE VALUE REVERSE( !_s_name_! ) WITH !_n_!'.'!_s_name_!
!_n_! = REVERSE( !_n_! )
!_s_name_! = REVERSE( !_s_name_! )
IF DATATYPE( !_n_!, 'W' ) THEN
DO
!_n_! = !_n_! + 1
CALL VALUE !_s_name_!'.0', !_n_!
END
!_s_name_! = !_s_name_!'.'!_n_!
END
ELSE
!_s_name_! = !_s_name_!'.'STRIP( TRANSLATE( !_key_! ),, '"' )
END
ELSE
!_s_name_! = !_s_name_!'.'STRIP( TRANSLATE( !_key_! ),, '"' )
ITERATE
END
!_stem_counter_! = !_stem_counter_! + 1
PARSE VALUE !_str_json_! WITH !_val_!','!_str_json_!
PARSE VALUE !_val_! WITH !_val_!'}'!_rest_!
!_key_! = SPACE( TRANSLATE( !_key_!,, !_not_in_key_range_! ), 0 )
IF POS( '"', !_val_! ) > 0 THEN
PARSE VALUE !_val_! WITH '"'!_val_!'"'
!_val_! = STRIP( STRIP( STRIP( STRIP( STRIP( STRIP( !_val_! ), 'T', D2C(10) ), 'T', D2C(13) ) ),, '"' ) )
CALL VALUE !_s_name_!'.'TRANSLATE( !_key_! ), !_val_!
CALL VALUE VALUE( stem )'.'!_stem_counter_!, !_s_name_!'.'TRANSLATE( !_key_! )
CALL VALUE VALUE( stem )'.0', !_stem_counter_!
IF ( !_end_brkt_! < !_key_val_sep_! | !_key_val_sep_! = 0 ) & ( !_end_brkt_! < !_end_sqr_brkt_! | !_end_sqr_brkt_! = 0 ) THEN
DO
!_n_! = ''
!_rest_! = '}'||SPACE( TRANSLATE( !_rest_!,, SPACE( TRANSLATE( XRANGE(),, '}]' ), 0 ) ), 0 )
DO WHILE LENGTH( !_rest_! ) > 0
PARSE VALUE !_rest_! WITH !_sign_! +1 !_rest_!
IF POS( '.', !_s_name_! ) > 0 THEN
DO
PARSE VALUE REVERSE( !_s_name_! ) WITH !_n_!'.'!_s_name_!
!_s_name_! = REVERSE( !_s_name_! )
!_n_! = REVERSE( !_n_! )
IF DATATYPE( !_n_!, 'W' ) & LEFT( !_rest_!, 1 ) <> ']' THEN
DO
!_n_! = !_n_! + 1
!_s_name_! = !_s_name_!'.'!_n_!
END
END
END
END
END
RETURN COUNTSTR( '.', !_s_name_! ) /* IF retval > 0 THEN INCOMPLETE FILE OR ERROR IN FUNCTION */

calc4Pos:
!_strt_sqr_brkt_! = POS( '[', !_str_json_! )
!_end_sqr_brkt_! = POS( ']', !_str_json_! )
!_strt_brkt_! = POS( '{', !_str_json_! )
!_end_brkt_! = POS( '}', !_str_json_! )
!_key_val_sep_! = POS( ',', !_str_json_! )
!_key_val_del_! = POS( ':', !_str_json_! )
RETURN 0


/* Count the number of occurances of needle in haystack from start pos to end pos (whole string by default) */
COUNTSTR: PROCEDURE /* needle, haystack< <, startpos>, endpos> */
IF TRACE() = '?I' THEN CALL TRACE 'O'
IF ARG() < 2 THEN RETURN -1
IF DATATYPE( ARG(3), 'W' ) THEN
next = ARG(3)
ELSE
next = 1
needle = ARG(1)
haystack = ARG(2)
IF DATATYPE( ARG(4), 'W' ) THEN
haystack = SUBSTR( haystack, next, ABS( ARG(4) - next ) )
next = 1
count = 0
DO WHILE next > 0
next = POS( needle, haystack, next )
IF next > 0 THEN DO
next = next + LENGTH( needle )
count = count + 1
END
END
RETURN count

[tygre]

Hi _amiga_!

This Rexx code comes from here?

What happens if you try to execute it?

Cheers!