src/awk/lib/util.awk

   1 function util_strip(s) {
   2     sub("^ *", "", s)
   3     sub(" *$", "", s)
   4     return s
   5 }
   6
   7 function util_round(n) {
   8     return int(n + 0.5)
   9 }
  10
  11 function util_ensure_numeric(n) {
  12     return n + 0
  13 }
  14
  15 #------------------------------------
  16 # Why do we need util_ensure_numeric?
  17 #------------------------------------
  18 # awk appears to be guessing the type of an inputted scalar based on usage, so
  19 # if we read-in a number, but did not use it in any numeric operations, but did
  20 # use as a string (even in just a format string!) - it will be treated as a
  21 # string and can lead to REALLY SURPRISING behavior in conditional statements,
  22 # where smaller number may compare as greater than the bigger ones, such as.
  23 #
  24 # Demo:
  25 #
  26 # $ awk 'BEGIN {x = "75"; y = "100"; sprintf("x: %d, y: %d\n", x, y); if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  27 # 75 < 100
  28 # $ awk 'BEGIN {x = "75"; y = "100"; sprintf("x: %s, y: %d\n", x, y); if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  29 # 75 > 100
  30
  31 # However, once used as a number, seems to stay that way even after being
  32 # used as string:
  33 #
  34 # $ awk 'BEGIN {x = "75"; y = "100"; x + y; sprintf("x: %s, y: %d\n", x, y); if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  35 # 75 < 100
  36 #
  37 # $ awk 'BEGIN {x = "75"; y = "100"; x + y; sprintf("x: %s, y: %d\n", x, y); z = x y; if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  38 # 75 < 100
  39 #
  40 # $ awk 'BEGIN {x = "75"; y = "100"; x + y; z = x y; if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  41 # 75 < 100
  42 # $ awk 'BEGIN {x = "75"; y = "100"; z = x y; if (x > y) {print "75 > 100"} else if (x < y) {print "75 < 100"}}'
  43 # 75 > 100