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1
4 package gnu.kawa.lispexpr;
5 import gnu.text.*;
6 import gnu.mapping.Values;
7
8 public class ReaderParens extends ReadTableEntry
9 {
10 char open;
11 char close;
12 int kind;
13
14 public int getKind()
15 {
16 return kind;
17 }
18
19 private static ReaderParens instance;
20
21 public static ReaderParens getInstance(char open, char close)
22 {
23 return getInstance(open, close, ReadTable.TERMINATING_MACRO);
24 }
25
26 public static ReaderParens getInstance(char open, char close, int kind)
27 {
28 if (open == '(' && close == ')' && kind == ReadTable.TERMINATING_MACRO)
29 {
30 if (instance == null)
31 instance = new ReaderParens(open, close, kind);
32 return instance;
33 }
34 else
35 {
36 return new ReaderParens(open, close, kind);
37 }
38 }
39
40 public ReaderParens(char open, char close, int kind)
41 {
42 this.open = open;
43 this.close = close;
44 this.kind = kind;
45 }
46
47
50 public Object  read (Lexer in, int ch, int count)
51 throws java.io.IOException , SyntaxException
52 {
53 return readList((LispReader) in, ch, count, close);
54 }
55
56 public static Object readList (LispReader lexer,
57 int ch, int count, int close)
58 throws java.io.IOException , SyntaxException
59 {
60 LineBufferedReader port = lexer.getPort();
61 char saveReadState = lexer.pushNesting(close == ']' ? '[' : '(');
62 int startLine = port.getLineNumber();
63 int startColumn = port.getColumnNumber();
64 try
65 {
66 Object last = null;
67 Object list = lexer.makeNil();
68 boolean sawDot = false;
69 boolean sawDotCdr = false;
70 ReadTable readTable = ReadTable.getCurrent();
71 for (;;)
72 {
73 int line = port.getLineNumber();
74 int column = port.getColumnNumber();
75 ch = port.read();
76 if (ch == close)
77 break;
78 if (ch < 0)
79 lexer.eofError("unexpected EOF in list starting here",
80 startLine + 1, startColumn);
81 ReadTableEntry entry;
82 if (ch == '.')
83 {
84 ch = port.peek();
85 entry = readTable.lookup(ch);
86 int kind = entry == null ? ReadTable.ILLEGAL : entry.getKind();
87 if (kind == ReadTable.WHITESPACE
88 || kind == ReadTable.TERMINATING_MACRO
89 || kind == ReadTable.ILLEGAL)
90 {
91 port.skip();
92 column++;
93 if (ch == close)
94 {
95 lexer.error("unexpected '"
96 + ((char) close) + "' after '.'");
97 break;
98 }
99 if (ch < 0)
100 lexer.eofError("unexpected EOF in list starting here",
101 startLine + 1, startColumn);
102 if (sawDot)
103 {
104 lexer.error("multiple '.' in list");
105 sawDotCdr = false;
106 list = lexer.makeNil();
107 last = null;
108 }
109 sawDot = true;
110 }
111 else
112 {
113 ch = '.';
115 entry = ReadTableEntry.getConstituentInstance();
116 }
117 }
118 else
119 entry = readTable.lookup(ch);
120 Object value = lexer.readValues(ch, entry, readTable);
121 if (value == Values.empty)
122 continue;
123 value = lexer.handlePostfix(value, readTable, line, column);
124
125
130 if (sawDotCdr)
131 {
132 lexer.error("multiple values after '.'");
133 last = null;
134 list = lexer.makeNil();
135 sawDotCdr = false;
136 continue;
137 }
138 else if (sawDot)
139 {
140 sawDotCdr = true;
141 }
142 else
143 {
144 if (last == null)
145 {
146 line = startLine;
147 column = startColumn-1;
148 }
149 value = lexer.makePair(value, line, column);
150 }
151 if (last == null)
152 list = value;
153 else
154 lexer.setCdr(last, value);
155 last = value;
156 }
157 return list;
158 }
159 finally
160 {
161 lexer.popNesting(saveReadState);
162 }
163
164 }
165 }
166 |
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