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  1. import java.io.BufferedReader;
  2. import java.io.InputStreamReader;
  3. import java.lang.StringBuilder;
  4.  
  5. class Lisp
  6. {
  7. 	public static final int VERSION_MAJOR    = 0;
  8. 	public static final int VERSION_MINOR    = 1;
  9. 	public static final int VERSION_REVISION = 0;
  10.  
  11. 	public static String getVersion()
  12. 	{
  13. 		return ( VERSION_MAJOR + "." + VERSION_MINOR + "." + VERSION_REVISION );
  14. 	}
  15.  
  16. 	public static void main( String[] args ) throws java.lang.Exception
  17. 	{
  18. 		Lisp lisp = new Lisp();
  19.  
  20. 		BufferedReader in = new BufferedReader( new InputStreamReader( System.in ) );
  21.  
  22. 		final String PROMPT1 = "LISP>";
  23. 		final String PROMPT2 = "    >";
  24. 		String prompt = PROMPT1;
  25. 		String line;
  26.  
  27. 		System.out.println( "-----------------------------------" );
  28. 		System.out.println( "        LISP   INTERPRETER         " );
  29. 		System.out.println( "-----------------------------------" );
  30. 		System.out.println( " Version " + Lisp.getVersion()       );
  31. 		System.out.println(                                       );
  32. 		System.out.println( " 'ctrl-z' to exit this interpreter " );
  33. 		System.out.println(                                       );
  34. 		System.out.println( "-----------------------------------" );
  35. 		System.out.println(                                       );
  36.  
  37. 		for (;;)
  38. 		{
  39. 			System.out.print( prompt + lisp.getIndent() );
  40.  
  41. 			line = in.readLine();
  42. 			if ( line == null )
  43. 			{
  44. 				break;
  45. 			}
  46.  
  47. 			line = line.trim();
  48. 			if ( line.length() == 0 )
  49. 			{
  50. 				continue;
  51. 			}
  52.  
  53. 			if ( line.charAt( 0 ) == ':' ) // System Command
  54. 			{
  55. 				line = line.toLowerCase();
  56. 				if (   ":quit".equals( line )
  57. 					|| ":exit".equals( line )
  58. 					|| ":bye" .equals( line ) )
  59. 				{
  60. 					break;
  61. 				}
  62. 				else
  63. 				{
  64. 					switch ( line )
  65. 					{
  66. 						case ":help":
  67. 							{
  68. 								System.out.println( "[Help]" );
  69. 								System.out.println( " :bye      same as ':exit'"            );
  70. 								System.out.println( " :cancel   cancel inputting lisp code" );
  71. 								System.out.println( " :exit     exit interpreter"           );
  72. 								System.out.println( " :help     show this help text"        );
  73. 								System.out.println( " :quit     same as ':exit'"            );
  74. 								System.out.println();
  75. 							}
  76. 							break;
  77.  
  78. 						case ":last":
  79. 							{
  80. 								System.out.println( "[Last Code]" );
  81. 								System.out.println( lisp.getLastCode() );
  82. 							}
  83. 							break;
  84.  
  85. 						case ":cancel":
  86. 							{
  87. 								System.out.println( "[Cancel]" );
  88. 								lisp.cancel();
  89. 								prompt = PROMPT1;
  90. 							}
  91. 							break;
  92.  
  93. 						default:
  94. 							{
  95. 								System.out.println( "Error!! Unknown Command! -> " + line );
  96. 							}
  97. 							break;
  98. 					}
  99. 					continue;
  100. 				}
  101. 			}
  102.  
  103. 			if ( lisp.input( line ) )
  104. 			{
  105. 				String result = lisp.excute();
  106. 				if ( result != null )
  107. 				{
  108. 					System.out.println( result );
  109. 				}
  110. 				else
  111. 				{
  112. 					System.out.println( "Error!!" );
  113. 					System.out.println( lisp.getErrorMessage() );
  114. 				}
  115. 				prompt = PROMPT1;
  116. 			}
  117. 			else
  118. 			{
  119. 				prompt = PROMPT2;
  120. 			}
  121. 		}
  122.  
  123. 	}
  124.  
  125. 	private int bracketcounter = 0;
  126. 	private StringBuilder lastcode;
  127.  
  128. 	public Lisp() {
  129. 		lastcode = new StringBuilder();
  130. 	}
  131.  
  132. 	public void cancel()
  133. 	{
  134. 		bracketcounter = 0;
  135. 	}
  136.  
  137. 	public boolean input( String src )
  138. 	{
  139. 		int sp = 0;
  140.  
  141. 		if ( bracketcounter == 0 )
  142. 		{
  143. 			lastcode.delete( 0 , lastcode.length() );
  144. 		}
  145. 		else
  146. 		{
  147. 			sp = -1;
  148. 		}
  149.  
  150. 		int len = src.length();
  151. 		for ( int i = 0 ; i < len ; i++ )
  152. 		{
  153. 			sp++;
  154. 			char ch = src.charAt( i );
  155. 			lastcode.append( ch );
  156. 			switch ( ch )
  157. 			{
  158. 				case ' ':
  159. 				case '\t':
  160. 				case '\n':
  161. 				case '\r':
  162. 					{
  163. 						if ( sp == 0 )
  164. 						{
  165. 							lastcode.delete( lastcode.length() - 1 , lastcode.length() );
  166. 						}
  167. 						sp = -1;
  168. 					}
  169. 					break;
  170.  
  171. 				case '(': // Open Bracket
  172. 					{
  173. 						bracketcounter++;
  174. 						sp = -1;
  175. 					}
  176. 					break;
  177.  
  178. 				case ')': // Close Bracket
  179. 					{
  180. 						if ( sp == 0 )
  181. 						{
  182. 							lastcode.delete( lastcode.length() - 2 , lastcode.length() - 1 );
  183. 						}
  184. 						bracketcounter--;
  185. 					}
  186. 					break;
  187.  
  188. 				case ';': // Comment
  189. 					{
  190. 						lastcode.delete( lastcode.length() - 1 , lastcode.length() );
  191. 						i = len;
  192. 						sp--;
  193. 					}
  194. 					break;
  195.  
  196. 				default: // Symbol (Atom)
  197. 					{
  198. 					}
  199. 					break;
  200. 			}
  201. 		}
  202. 		if ( sp >= 0 && bracketcounter > 0 )
  203. 		{
  204. 			lastcode.append( ' ' );
  205. 		}
  206. 		return ( bracketcounter == 0 );
  207. 	}
  208.  
  209. 	public String excute()
  210. 	{
  211. 		return ( null );
  212. 	}
  213.  
  214. 	public String getErrorMessage()
  215. 	{
  216. 		return ( "" );
  217. 	}
  218.  
  219. 	public String getLastCode()
  220. 	{
  221. 		return ( lastcode.toString() );
  222. 	}
  223.  
  224. 	public String getIndent()
  225. 	{
  226. 		final String spacer = "                    ";
  227. 		if ( bracketcounter == 0 )
  228. 		{
  229. 			return ( "" );
  230. 		}
  231. 		else if ( bracketcounter * 2 < spacer.length() )
  232. 		{
  233. 			return ( spacer.substring( spacer.length() - bracketcounter * 2 ) );
  234. 		}
  235. 		else
  236. 		{
  237. 			return ( spacer );
  238. 		}
  239. 	}
  240. }
Success #stdin #stdout 0.06s 380224KB
comments (?)
stdin
copy 
:help
(hoge
aiueo ;; comment line
fuga)
:last
(foo
bar
:cancel
:last
stdout
copy 
-----------------------------------
        LISP   INTERPRETER         
-----------------------------------
 Version 0.1.0

 'ctrl-z' to exit this interpreter 

-----------------------------------

LISP>[Help]
 :bye      same as ':exit'
 :cancel   cancel inputting lisp code
 :exit     exit interpreter
 :help     show this help text
 :quit     same as ':exit'

LISP>    >      >  Error!!

LISP>[Last Code]
(hoge aiueo fuga)
LISP>    >      >  [Cancel]
LISP>[Last Code]
(foo bar 
LISP>
https://ideone.com/PgYNk6
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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