# -*- rexx -*-

# hello world
# print a simple string on stdout
say "Hello World"

# argv
# access command line parameters (no segmentation fault accepted, nor silent exception, so some languages must explicitly check the presence of the argument)
say ARG(1)

# env
# access environment variable
say VALUE("HOME", , SYSTEM)

# test file exists
# return exit code error (non zero) if a file does not exist
exit STREAM(ARG(1), 'C', 'QUERY EXISTS') == ""

# test file readable
# return exit code error (non zero) if a file is not readable
exit \STREAM(ARG(1), 'C', 'READABLE')

# formatting
# print integers in a simple formatted string
a = 1 ; b = 2 ; say a "+" b "=" a + b

# system
# call an external program and check the return value
address SYSTEM "false"
if RC == 0 then ; call LINEOUT 'STDERR', "false failed"
address SYSTEM "echo done"


# sed in place
# remove #-comments from a file (modifying the file, i.e. in place)
call rxFuncAdd 'sysLoadFuncs', 'rexxUtil', 'sysLoadFuncs'
call sysLoadFuncs

fin = ARG(1) ; fout = RANDOM() || ".tmp"
do while LINES(fin) > 0
  call LINEOUT fout, CHANGESTR("#", LINEIN(fin), "")
end
call STREAM fin, 'C', 'CLOSE' ; call STREAM fout, 'C', 'CLOSE'

call sysFileDelete fin ; call sysMoveObject fout, fin
call sysDropFuncs


# compile what must be
# find and compile .c files into .o when the .o is old or absent
call rxFuncAdd 'sysLoadFuncs', 'rexxUtil', 'sysLoadFuncs'
call sysLoadFuncs

call sysFileTree '*.c', 'cfilelist.', 'sf'

do i = 1 for cfilelist.0
  cfilelist.i = WORD(cfilelist.i, 5)
  ofile = LEFT(cfilelist.i, LASTPOS(".c", cfilelist.i) - 1) || ".o"
  otime = STREAM(ofile, 'C', 'QUERY TIMESTAMP')
  if otime < STREAM(cfilelist.i, 'C', 'QUERY TIMESTAMP') then do
    say "compiling" cfilelist.i "to" ofile
    address SYSTEM "gcc -c -o" cfilelist.i ofile
  end
end

call sysDropFuncs


# grep
# grep with -F -i -h handling, usage, grep'ing many files
call rxFuncAdd 'reLoadFuncs', 'rexxRE', 'reLoadFuncs'
call reLoadFuncs

cmdline = ARG(1) ; opt = "" ; regexp = "" ; filelist = ""

do while cmdline <> ""
  parse var cmdline token cmdline
  if LEFT(token, 1) == "-" then
    if TRANSLATE(token) == "-H" | VERIFY(token, "-iF") \= 0 then
      call usage ; else ; opt = opt || CHANGESTR("-", token, "")
  else ; if regexp == "" then
    regexp = token
  else
    filelist = filelist token
end

/* 'F' not recognised by 'reComp'; just remove it */
opt = CHANGESTR("F", opt, "")
if POS("i", opt) > 0 then ; opt = "" ; else ; opt = "c"

cre = reComp(regexp, opt)

do while filelist <> ""
  parse var filelist file filelist
  do while LINES(file) > 0
    if reExec(cre, LINEIN(file), 'match.') then
      call LINEOUT , file || ":" || match.!match
  end
end

call reFree cre ; call reDropFuncs ; exit 0

usage :
  say "usage: grep [-h] | [-F|-i] regexp [files...]"
  call reDropFuncs ; exit 1