awk/step1_read_print.awk

   1 @include "types.awk"
   2 @include "reader.awk"
   3 @include "printer.awk"
   4
   5 function READ(str)
   6 {
   7         return reader_read_str(str)
   8 }
   9
  10 function EVAL(ast)
  11 {
  12         return ast
  13 }
  14
  15 function PRINT(expr)
  16 {
  17         return printer_pr_str(expr, 1)
  18 }
  19
  20 function rep(str,    ast, expr)
  21 {
  22         ast = READ(str)
  23         if (ast ~ /^!/) {
  24                 return ast
  25         }
  26         expr = EVAL(ast)
  27         if (expr ~ /^!/) {
  28                 return expr
  29         }
  30         return PRINT(expr)
  31 }
  32
  33 function main(str, ret)
  34 {
  35         while (1) {
  36                 printf("user> ")
  37                 if (getline str <= 0) {
  38                         break
  39                 }
  40                 ret = rep(str)
  41                 if (ret ~ /^!/) {
  42                         print "ERROR: " printer_pr_str(substr(ret, 2))
  43                 } else {
  44                         print ret
  45                 }
  46         }
  47 }
  48
  49 BEGIN {
  50         main()
  51         exit(0)
  52 }