Other notes

"=" character can be used both for assignment and for a comparison, though it's possible to use "EQ" in the latter case: 

       V.STRING = 'ABC'
       IF V.STRING = 'ABC' THEN CRT 'YES'
       IF V.STRING EQ 'ABC' THEN CRT 'YES AGAIN'

"Non-equal" can either be "#", "!", "<>" or "NE": 

       a_string = 'ABC'
       IF a_string #  'A' THEN CRT 'Not an "A"'
       IF a_string NE 'B' THEN CRT 'Not a "B"'
       IF a_string ! 'C' THEN CRT 'Not even a "C"'
       IF a_string <> 'D' THEN CRT 'Surprisingly, but neither a "D"'

IF...ELSE construct can be used without THEN: 

       V.STRING = 'ABC'
       IF V.STRING NE 'ABC' ELSE CRT 'YES'

Differences between emulations

For T24 emulation should always be prime, however for porting the code it's crucial to understand the differences.

See several examples below.

The following code will run successfully under prime emulation and will fail under ros: 

       ret_code = GETENV('JBCEMULATE', jbc_emu)   ;   CRT jbc_emu
       dyn_array = 3 :@AM: 7
       dyn_array += 4
       CRT FMT(dyn_array, 'MCP')

Runtime: 

     prime
     7^7

     ros
     Non-numeric value -- ZERO USED ,
     Variable 'dyn_array' , Line     3 , Source test.b
     Trap from an error message, error message name = NON_NUMERIC

Setting in Config_EMULATE: no_value_maths = false|true

Next program outputs <> under prime and <0> under seq emulation. In the latter case there will be zero-sized file report.txt after program termination. So if, for example, nothing was written to a report under prime emulation (or, in fact, any other except seq), there will be no output file left after that.

Source code: 

       dir_name = '.'
       file_name = 'report.txt'
       DELETESEQ dir_name, file_name ELSE NULL
       *
       OPENSEQ dir_name, file_name TO f_report THEN NULL
       CRT '<' : DIR(file_name)<1> : '>'

Setting in Config_EMULATE: openseq_creates = false|true

The following program outputs 1 under prime emulation and 0 under r83, thus showing that common variables can be assigned or unassigned upon declaration of COMMON area: 

       COMMON /MY.COMM/ var_1, var_2
       *
       CRT ASSIGNED(var_1)

Setting in Config_EMULATE: named_common = unassigned|null|zero

The next program outputs A^1^2^3^4^5 under seq or r83 emulations; under others (that do add additional delimiter even if one exists at the end of an array in question) the output will be: A^^1^2^3^4^5.

Source code: 

       dyn_array = 'A' : @FM
       FOR i = 1 TO 5
          dyn_array<-1> = i
       NEXT i
       CRT OCONV(dyn_array, 'MCP')

Setting in Config_EMULATE: no_extra_delimiter = false|true

The following READV example outputs REC1 (i.e. record key) when is run under jbase emulation and 3 (i.e. fields count) under, e.g., ap or r83: 

       OPEN 'F.TEMP' TO f_temp THEN
          ret_error = ''
          CLEARFILE f_temp SETTING ret_error
          IF ret_error NE '' THEN
             CRT 'ERROR ' : ret_error
             STOP
          END
       END ELSE
          EXECUTE 'CREATE-FILE DATA F.TEMP 1 101 TYPE=J4'
          OPEN 'F.TEMP' TO f_temp ELSE ABORT 201, 'F.TEMP'
       END
       *
       out_record = 'LINE 1' :@FM: 'LINE 2' :@FM: 'LINE 3'
       WRITE out_record TO f_temp, 'REC1'
       *
       READV in_record FROM f_temp, 'REC1', 0 ELSE
          CRT 'Read error'
          STOP
       END
       *
       CRT in_record

Setting in Config_EMULATE: readv0 = key|dcount|binary

Some settings are effective at runtime, others apply during compilation. For example, the following program compiles successfully under prime emulation and runs successfully after that under all emulations. However, it's not possible to compile it under, say, jbase emulation. Reason of error - redimensioning of an array.

Code: 

       DIMENSION dyn_array(10)
       MAT dyn_array = '!'
       dyn_array(5) = '?'
       FOR i = 1 TO 10
          CRT dyn_array(i):          ;* !!!!?!!!!!
       NEXT i
       DIM dyn_array(15)
       dyn_array(15) = '...'
       CRT dyn_array(15)

Compilation under jbase emulation: 

     [error 1        (32)] "test.b", 7 (offset 18)  near ")":
     Array dyn_array has already been DIMensioned
      
     1 error was found

Setting in Config_EMULATE: resize_array = false|true

Another example: 

    * number of seconds past midnight
       CRT SYSTEM(12)   ;* e.g. 30938703.4097 under prime, 309387 under ros

For more settings see Config_EMULATE and Config_EMULATE.txt files in your TAFC/config folder.

Last update: Sat, 16 Jul 2022 15:34