I don't at all know what Tcl is, I know to program in C/C++. This is the first occasion I have ever come across Tcl.
I was in the process of developing some software in C/C++ and there was a piece of Tcl code given in a document to explain how CRC-8-ATM needs to be computed. I have to implement a C version of this piece of code. I wanted to understand how this code works so I used codepad.org to run the code over there, but when I submit the code I get an error as:
wrong # args: should be "proc name args body"
while executing
"proc crc8{}"
(file "t.tcl" line 1)
Can somebody please help me with this error? And finally print the CRC value.
proc crc8{}
{
set crc_input {0x05 0x3D 0x09 0x89}
set poly_table
{
0x00 0x07 0x0E 0x09 0x1C 0x1B 0x12 0x15 0x38
0x3F 0x36 0x31 0x24 0x23 0x2A 0x2D 0x70 0x77
0x7E 0x79 0x6C 0x6B 0x62 0x65 0x48 0x4F 0x46
0x41 0x54 0x53 0x5A 0x5D 0xE0 0xE7 0xEE 0xE9
0xFC 0xFB 0xF2 0xF5 0xD8 0xDF 0xD6 0xD1 0xC4
0xC3 0xCA 0xCD 0x90 0x97 0x9E 0x99 0x8C 0x8B
0x82 0x85 0xA8 0xAF 0xA6 0xA1 0xB4 0xB3 0xBA
0xBD 0xC7 0xC0 0xC9 0xCE 0xDB 0xDC 0xD5 0xD2
0xFF 0xF8 0xF1 0xF6 0xE3 0xE4 0xED 0xEA 0xB7
0xB0 0xB9 0xBE 0xAB 0xAC 0xA5 0xA2 0x8F 0x88
0x81 0x86 0x93 0x94 0x9D 0x9A 0x27 0x20 0x29
0x2E 0x3B 0x3C 0x35 0x32 0x1F 0x18 0x11 0x16
0x03 0x04 0x0D 0x0A 0x57 0x50 0x59 0x5E 0x4B
0x4C 0x45 0x42 0x6F 0x68 0x61 0x66 0x73 0x74
0x7D 0x7A 0x89 0x8E 0x87 0x80 0x95 0x92 0x9B
0x9C 0xB1 0xB6 0xBF 0xB8 0xAD 0xAA 0xA3 0xA4
0xF9 0xFE 0xF7 0xF0 0xE5 0xE2 0xEB 0xEC 0xC1
0xC6 0xCF 0xC8 0xDD 0xDA 0xD3 0xD4 0x69 0x6E
0x67 0x60 0x75 0x72 0x7B 0x7C 0x51 0x56 0x5F
0x58 0x4D 0x4A 0x43 0x44 0x19 0x1E 0x17 0x10
0x05 0x02 0x0B 0x0C 0x21 0x26 0x2F 0x28 0x3D
0x3A 0x33 0x34 0x4E 0x49 0x40 0x47 0x52 0x55
0x5C 0x5B 0x76 0x71 0x78 0x7F 0x6A 0x6D 0x64
0x63 0x3E 0x39 0x30 0x37 0x22 0x25 0x2C 0x2B
0x06 0x01 0x08 0x0F 0x1A 0x1D 0x14 0x13 0xAE
0xA9 0xA0 0xA7 0xB2 0xB5 0xBC 0xBB 0x96 0x91
0x98 0x9F 0x8A 0x8D 0x84 0x83 0xDE 0xD9 0xD0
0xD7 0xC2 0xC5 0xCC 0xCB 0xE6 0xE1 0xE8 0xEF
0xFA 0xFD 0xF4 0xF3
}
set crc 255
foreach int $crc_input
{
set crc [lindex $poly_table [expr ($crc^$int) & 0xFF]]
}
return $crc
}
The problem is on these lines:
proc crc8{}
{
Because Tcl really cares about putting spaces between things, and treats newline as a statement terminator, you have to write them as:
proc crc8 {} {
(You could also use a backslash at the end of the line to prevent the newline from being a terminator, but that's much less elegant. And you still need a space between the procedure name and the formal argument list. Going full “one true brace” saves a lot of effort.)
You will have a similar problem with the set poly_table and the foreach. Move the { on the line following to the end of the preceding line with a space separating it from what went before.