├── catlang ├── assets ├── hello_from_miumiu.jpeg └── hello_from_momo.jpeg ├── LICENSE ├── helloworld.cat ├── README.md └── catlang.cpp /catlang: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/hxu296/catlang/HEAD/catlang -------------------------------------------------------------------------------- /assets/hello_from_miumiu.jpeg: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/hxu296/catlang/HEAD/assets/hello_from_miumiu.jpeg -------------------------------------------------------------------------------- /assets/hello_from_momo.jpeg: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/hxu296/catlang/HEAD/assets/hello_from_momo.jpeg -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) 2022 Huan Xu 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /helloworld.cat: -------------------------------------------------------------------------------- 1 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 2 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 3 | mEoW mEoW mEow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEoW mEoW 4 | mEoW mEoW mEoW mEoW mEoW mEow mEow mEoW mEoW mEoW mEow Meow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 5 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 6 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 7 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW 8 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEOw 9 | mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw 10 | mEOw mEOw mEOw mEOw mEOw mEow mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEow mEoW mEoW mEoW mEow mEOw mEOw mEOw mEOw mEOw mEOw mEow mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEow 11 | Meow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow 12 | 13 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | ## About 2 | Here we define the cat language with the following syntax: 3 | |Code|Instruction|Description| 4 | | ----- | ----- | ----- | 5 | |0|meow|This command is connected to the mEOW command. When encountered during normal execution, it searches the program code in reverse looking for a matching mEOW command and begins executing again starting from the found mEOW command. When searching, it skips the instruction that is immediately before it (see mEOW).| 6 | |1|meOw|Moves current memory position back one block.| 7 | |2|meoW|Moves current memory position forward one block.| 8 | |3|meOW|Execute value in current memory block as if it were an instruction. The command executed is based on the instruction code value (for example, if the current memory block contains a 2, then the meoW command is executed). An invalid command exits the running program. Value 3 is invalid as it would cause an infinite loop.| 9 | |4|mEow|If current memory block has a 0 in it, read a single ASCII character from STDIN and store it in the current memory block. If the current memory block is not 0, then print the ASCII character that corresponds to the value in the current memory block to STDOUT.| 10 | |5|mEOw|Decrement current memory block value by 1.| 11 | |6|mEoW|Increment current memory block value by 1.| 12 | |7|mEOW|If current memory block value is 0, skip next command and resume execution after the next matching meow command. If current memory block value is not 0, then continue with next command. Note that the fact that it skips the command immediately following it has interesting ramifications for where the matching meow command really is. For example, the following will match the second and not the first meow: Meow mEOW meow meow| 13 | |8|Meow|Set current memory block value to 0.| 14 | |9|MEow|If no current value in register, copy current memory block value. If there is a value in the register, then paste that value into the current memory block and clear the register.| 15 | |10|MeOw|Print value of current memory block to STDOUT as an integer.| 16 | |11|MeoW|Read an integer from STDIN and put it into the current memory block.| 17 | 18 | ## Example 19 | Try out the [catlang interpreter](https://github.com/hxu296/catlang/blob/main/catlang.cpp) and the hello world program that prints "Hello, world!" to STDOUT: 20 | ```bash 21 | g++ -o catlang catlang.cpp 22 | ./catlang helloworld.cat 23 | ``` 24 | The [helloword.cat](https://github.com/hxu296/catlang/blob/main/helloworld.cat) program: 25 | ``` 26 | mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEow mEoW mEoW mEoW mEow Meow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEow mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEow mEoW mEoW mEoW mEow mEOw mEOw mEOw mEOw mEOw mEOw mEow mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEOw mEow Meow mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEoW mEow 27 | ``` 28 | 29 | ## Acknowledgement 30 | Inspired by *[the COW project](https://bigzaphod.github.io/COW/)* and by our family members **momo** (first) and **miumiu** (second): 31 | ![momo](./assets/hello_from_momo.jpeg) 32 | ![miumiu](./assets/hello_from_miumiu.jpeg) 33 | -------------------------------------------------------------------------------- /catlang.cpp: -------------------------------------------------------------------------------- 1 | //-------------------------------------------- 2 | // CAT PROGRAMMING LANGUAGE 3 | // author: Huan Xu 4 | // credit to: BigZaphod sean@fifthace.com 5 | //-------------------------------------------- 6 | #include 7 | #include 8 | #include 9 | #include 10 | 11 | typedef std::vector mem_t; 12 | mem_t program; 13 | mem_t memory; 14 | mem_t::iterator mem_pos; 15 | mem_t::iterator prog_pos; 16 | 17 | int register_val; 18 | bool has_register_val = false; 19 | 20 | void quit( bool error ) 21 | { 22 | if( error ) 23 | { 24 | printf( "\nERROR!\n" ); 25 | exit(1); 26 | } 27 | } 28 | 29 | bool exec( int instruction ) 30 | { 31 | 32 | switch( instruction ) 33 | { 34 | // meow 35 | case 0: 36 | { 37 | if( prog_pos == program.begin() ) 38 | quit( true ); 39 | 40 | prog_pos--; // skip previous command. 41 | int level = 1; 42 | while( level > 0 ) 43 | { 44 | if( prog_pos == program.begin() ) 45 | break; 46 | 47 | prog_pos--; 48 | 49 | if( (*prog_pos) == 0 ) 50 | level++; 51 | else 52 | if( (*prog_pos) == 7 ) // look for mEOW 53 | level--; 54 | } 55 | 56 | if( level != 0 ) 57 | quit(true); 58 | 59 | return exec( *prog_pos ); 60 | } 61 | 62 | // meOw 63 | case 1: 64 | if( mem_pos == memory.begin() ) 65 | quit( true ); 66 | else 67 | mem_pos--; 68 | break; 69 | 70 | // meoW 71 | case 2: 72 | mem_pos++; 73 | if( mem_pos == memory.end() ) 74 | { 75 | memory.push_back(0); 76 | mem_pos = memory.end(); 77 | mem_pos--; 78 | } 79 | break; 80 | 81 | // meOW 82 | case 3: 83 | if( (*mem_pos) == 3 ) 84 | quit( false ); 85 | return exec(*mem_pos); 86 | 87 | // mEow 88 | case 4: 89 | if( (*mem_pos) != 0 ) 90 | printf( "%c", *mem_pos ); 91 | else 92 | { 93 | (*mem_pos) = getchar(); 94 | while( getchar() != '\n' ); 95 | } 96 | break; 97 | 98 | // mEOw 99 | case 5: 100 | (*mem_pos)--; 101 | break; 102 | 103 | // mEoW 104 | case 6: 105 | (*mem_pos)++; 106 | break; 107 | 108 | // mEOW 109 | case 7: 110 | if( (*mem_pos) == 0 ) 111 | { 112 | int level = 1; 113 | int prev = 0; 114 | prog_pos++; // have to skip past next command when looking for next meow. 115 | if( prog_pos == program.end() ) 116 | break; 117 | while( level > 0 ) 118 | { 119 | prev = *prog_pos; 120 | prog_pos++; 121 | 122 | if( prog_pos == program.end() ) 123 | break; 124 | 125 | if( (*prog_pos) == 7 ) 126 | level++; 127 | else 128 | if( (*prog_pos) == 0 ) // look for meow command. 129 | { 130 | level--; 131 | if( prev == 7 ) 132 | level--; 133 | } 134 | } 135 | if( level != 0 ) 136 | quit( true ); 137 | } 138 | break; 139 | 140 | // Meow 141 | case 8: 142 | (*mem_pos) = 0; 143 | break; 144 | 145 | // MEow 146 | case 9: 147 | if( has_register_val ) 148 | (*mem_pos) = register_val; 149 | else 150 | register_val = (*mem_pos); 151 | has_register_val = !has_register_val; 152 | break; 153 | 154 | // MeOw 155 | case 10: 156 | printf( "%d\n", *mem_pos ); 157 | break; 158 | 159 | // MeoW 160 | case 11: 161 | { 162 | char buf[100]; 163 | int c = 0; 164 | while( c < sizeof(buf)-1 ) 165 | { 166 | buf[c] = getchar(); 167 | c++; 168 | buf[c] = 0; 169 | 170 | if( buf[c-1] == '\n' ) 171 | break; 172 | } 173 | // swallow, just in case. 174 | if( c == sizeof(buf) ) 175 | while( getchar() != '\n' ); 176 | 177 | (*mem_pos) = atoi( buf ); 178 | 179 | break; 180 | } 181 | 182 | // bad stuff 183 | default: 184 | quit( false ); 185 | }; 186 | 187 | prog_pos++; 188 | 189 | return true; 190 | } 191 | 192 | 193 | int main( int argc, char** argv ) 194 | { 195 | if( argc < 2 ) 196 | { 197 | printf( "Usage: %s program.cat\n\n", argv[0] ); 198 | exit( 1 ); 199 | } 200 | 201 | FILE* f = fopen( argv[1], "rb" ); 202 | 203 | if( f == NULL ) 204 | { 205 | printf( "Cannot open source file [%s].\n", argv[1] ); 206 | exit( 1 ); 207 | } 208 | 209 | char buf[4]; 210 | memset( buf, 0, 4 ); 211 | int pos = 0; 212 | 213 | while( !feof(f) ) 214 | { 215 | int found = 0; 216 | buf[3] = fgetc( f ); 217 | 218 | if( found = !strncmp( "meow", buf, 4 ) ) 219 | program.push_back( 0 ); 220 | else if( found = !strncmp( "meOw", buf, 4 ) ) 221 | program.push_back( 1 ); 222 | else if( found = !strncmp( "meoW", buf, 4 ) ) 223 | program.push_back( 2 ); 224 | else if( found = !strncmp( "meOW", buf, 4 ) ) 225 | program.push_back( 3 ); 226 | else if( found = !strncmp( "mEow", buf, 4 ) ) 227 | program.push_back( 4 ); 228 | else if( found = !strncmp( "mEOw", buf, 4 ) ) 229 | program.push_back( 5 ); 230 | else if( found = !strncmp( "mEoW", buf, 4 ) ) 231 | program.push_back( 6 ); 232 | else if( found = !strncmp( "mEOW", buf, 4 ) ) 233 | program.push_back( 7 ); 234 | else if( found = !strncmp( "Meow", buf, 4 ) ) 235 | program.push_back( 8 ); 236 | else if( found = !strncmp( "MEow", buf, 4 ) ) 237 | program.push_back( 9 ); 238 | else if( found = !strncmp( "MeOw", buf, 4 ) ) 239 | program.push_back( 10 ); 240 | else if( found = !strncmp( "MeoW", buf, 4 ) ) 241 | program.push_back( 11 ); 242 | 243 | if( found ) 244 | { 245 | memset( buf, 0, 4 ); 246 | } 247 | else 248 | { 249 | buf[0] = buf[1]; 250 | buf[1] = buf[2]; 251 | buf[2] = buf[3]; 252 | buf[3] = 0; 253 | } 254 | } 255 | 256 | fclose( f ); 257 | 258 | 259 | // init main memory. 260 | memory.push_back( 0 ); 261 | mem_pos = memory.begin(); 262 | 263 | prog_pos = program.begin(); 264 | while( prog_pos != program.end() ) 265 | if( !exec( *prog_pos ) ) 266 | break; 267 | 268 | quit( false ); 269 | 270 | return 0; 271 | } 272 | 273 | 274 | --------------------------------------------------------------------------------