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	Tiny CSV Reader V. Program through tests 201507 To get the program to pass the test file, there has been no straight way. The major problem is that I tried to solve the problem like working on an exercise from the theoretical computer science textbook ( automaton, regular language). package net.heteroclinic.tinycsv; import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.junit.Test; /** * <p/> * <p/> * Tiny CSV Reader * <p>Third party licenses/rights are automatically cascaded.</p> * Given you keep this header, you can do anything with this program. * @author Zhikai Wang/www.heteroclinic.net * Reference " https://en.wikipedia.org/wiki/Comma-separated_values last retrieved June,2015. / // Note : http://docs.oracle.com/javase/tutorial/essential/regex/bounds.html -- 20150706 // says $ is The end of a line in fact in (?s) mode it is end of String // end of line should be system property line separator. public class TestRegex { @Test public void testSplit() { { System.out.println("\n=== 1 ===="); String data = ","; String [] arr = data.split(","); System.out.println(arr.length); System.out.print("\|"); for (String s : arr) { System.out.print(s+"\|"); } } { System.out.println("\n=== 2 ===="); String data = "a,"; String [] arr = data.split(","); System.out.println(arr.length); System.out.print("\|"); for (String s : arr) { System.out.print(s+"\|"); } } { System.out.println("\n=== 3 ===="); String data = ",b"; String [] arr = data.split(","); System.out.println(arr.length); System.out.print("\|"); for (String s : arr) { System.out.print(s+"\|"); } } } //TODO Find two quotes each time then new line @Test public void testFindTwoQuotesNewLineLoop () throws FileNotFoundException { { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); //final String data = "asbc\ndef\n\"cdf\ntpq"; System.out.println("=== 5 find 1. string has even quotes + new line or 2. string has no quotes with + new line added last match==="); // the or conditions should be mutual exclude or the parser may be confused. maybe that is former cases are not expected. Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(\\G" + "([^\\\"]?)" + "([\\\n]\|$))" + "\|" + "(\\G" + "((([^\\\n]?)[\\\"](.?)[\\\"]([^\\\n]?))+?)" + "([\\\n]\|$))" + ")" ); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { //final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); final String data = "asbc\ndef\n\"cdf\ntpq"; System.out.println("=== 4 find string has no quote end with new line since last match==="); // the or conditions should be mutual exclude or the parser may be confused. maybe that is former cases are not expected. Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "\\G" + "([^\\\"]?)" + "([\\\n]\|$)" + ")" ); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 3 find string has no quote end with new line ==="); // the or conditions should be mutual exclude or the parser may be confused. maybe that is former cases are not expected. Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "([^\\\"]?)" + "([\\\n]\|$)" + ")" ); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 2 find string has exactly two quotes ==="); // the or conditions should be mutual exclude or the parser may be confused. maybe that is former cases are not expected. Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(.?)[\\\"](.?)[\\\"]" + ")" ); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 1 find 1. string has two quotes or 2. no quotes with end of line==="); // the or conditions should be mutual exclude or the parser may be confused. maybe that is former cases are not expected. Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(.?)[\\\"](.?)[\\\"]" + ")" + "\|" + "(([^\\\"].?)([\\\n]))"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } } @Test public void testFindTwoQuotes () throws FileNotFoundException { // not working well { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 4 find quotes appearing even times (including zero?) and nearest return==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "((([^\\\"]?)[\\\"]([^\\\"]?)[\\\"]([^\\\"]?))?)" + "([\\\n]\|$)" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 3 find two quotes ONLY and nearest return==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "([^\\\"]?)[\\\"]([^\\\"]?)[\\\"]([^\\\"]?)[\\\n]" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 2 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(.?)[\\\"](.?)[\\\"](.?)[\\\n]" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 1 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(.?)[\\\"](.?)[\\\"]" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } } @Test public void testParseRecords () throws FileNotFoundException { {//missing line final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile2").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 4 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" //+ "((((.?)[\\\"](.?))((.?)[\\\"](.?)))?)" + "((((.?)[\\\"](.?)[\\\"](.?))?)\|([^\\\"]?))" + "([\\\n]\|$)" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } { final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 3 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" //+ "((((.?)[\\\"](.?))((.?)[\\\"](.?)))?)" + "((((.?)[\\\"](.?)[\\\"](.?))?)\|([^\\\"]?))" + "([\\\n]\|$)" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } {//missing rows, wrong final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 2 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "(.?)((((.?)[\\\"](.?))((.?)[\\\"](.?)))?)(.?)" + "([\\\n]\|$)" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } {//missing rows final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); System.out.println("=== 1 ==="); Pattern patternForRecord = Pattern.compile("(?s)" + "(" + "((((.?)[\\\"](.?))((.?)[\\\"](.?)))?)" + "([\\\n])" + ")"); Matcher m = patternForRecord.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } } } //TODO test quotes appear even times @Test public void testFindNewLineAfterEvenQuotesCount () { final String data = "\"\n\"\n" + "\"\"\"\"\n" + "\"\"\n\"\"\n" + "a\"\"\"\"\n\n" + "a\"aa\na\"\"bbb\"\n" + "\"\"\"\"\"\n\"\"\"\n"; { System.out.println("=== 2 ==="); Pattern p = Pattern.compile("(?s)" + "(" + "(((.?)[\\\"](.?))((.?)[\\\"](.?)))?" + "[\\\n]" + ")"); Matcher m = p.matcher(data); while (m.find()) { System.out.println("\|"+data.substring(m.start(), m.end())+"\|"); System.out.println("----"); } / === 2 === \|" " \| ---- \|"""" \| ---- \|"" \| ---- \|"" \| ---- \|a"""" \| ---- \| \| ---- \|a"aa a""bbb" \| ---- \|""""" """ \| ---- / } } @Test public void testSwitchPatternsNotWork () { final String data = "aaa\n" + "b,bb\n" + "aaa\n" + "b,bb\n" + "b,bb\n" + "ccc"; Pattern p1 = Pattern.compile("(?s)(a?)([,]\|[\\\n]\|$)"); Matcher m1 = p1.matcher(data); Pattern p2 = Pattern.compile("(?s)(b?)([,]\|[\\\n]\|$)"); // infinite loop // while (m1.find()) { // System.out.println("\|"+data.substring(m1.start(), m1.end())+"\|"); // m1 = p2.matcher(data); // } } @Test public void testGroup () { // TODO test group final String data1 = "aa,a\n" + "bbb\n"; final String data2 = "aaa\n" + "b,bb\n" + "ccc"; { Pattern p1 = Pattern.compile("((a?)\|(b?)\|(c?))([,]\|[\\\n]\|$)"); Matcher m1 = p1.matcher(data1); Pattern p2 = Pattern.compile("((a?)\|(b?)\|(c?))([,]\|[\\\n]\|$)"); Matcher m2 = p2.matcher(data2); System.out.println("1"); while (m1.find()) { //System.out.println("m1.start()="+m1.start()); //System.out.println("m1.end()="+m1.end());//Returns the offset after the last character matched. System.out.println("\|"+data1.substring(m1.start(), m1.end())+"\|"); } System.out.println("2"); while (m2.find()) { //System.out.println("m2.start()="+m2.start()); //System.out.println("m2.end()="+m2.end()); System.out.println("\|"+data2.substring(m2.start(), m2.end())+"\|"); } } / 1 \|aa,\| \|a \| \|bbb \| \|\| 2 \|aaa \| \|b,\| \|bb \| \|ccc\| \|\| / } // TODO test or condition @Test public void testOrCondition () { final String data1 = "aa,a\n" + "bbb\n"; final String data2 = "aaa\n" + "b,bb\n" + "ccc"; { System.out.println("1"); Pattern p1 = Pattern.compile("(?s),\|[\\\n]"); Matcher m1 = p1.matcher(data1); Matcher m2 = p1.matcher(data2); while (m1.find()) { System.out.println("m1.start()="+m1.start()); System.out.println("m1.end()="+m1.end());//Returns the offset after the last character matched. } while (m2.find()) { System.out.println("m2.start()="+m2.start()); System.out.println("m2.end()="+m2.end()); } } } @Test public void testMisc () { //System.out.println(System.getProperty("line.separator")); ="\n" // input is a Java String final String data1 = "aaa\n" + "bbb\n"; final String data2 = "aaa\n" + "bbb\n" + "ccc"; // TODO find line separator { System.out.println("1"); Pattern p1 = Pattern.compile("(?s).?[\\\n]"); Matcher m1 = p1.matcher(data1); Matcher m2 = p1.matcher(data2); while (m1.find()) { System.out.println("m1.start()="+m1.start()); System.out.println("m1.end()="+m1.end());//Returns the offset after the last character matched. } while (m2.find()) { System.out.println("m2.start()="+m2.start()); System.out.println("m2.end()="+m2.end()); } } // TODO find $ { System.out.println("2"); Pattern p1 = Pattern.compile("(?s).?$"); Matcher m1 = p1.matcher(data1); Matcher m2 = p1.matcher(data2); while (m1.find()) { System.out.println("m1.start()="+m1.start()); System.out.println("m1.end()="+m1.end()); } while (m2.find()) { System.out.println("m2.start()="+m2.start()); System.out.println("m2.end()="+m2.end()); } } // TODO find System.getProperty("line.separator") { System.out.println("3"); Pattern p1 = Pattern.compile("(?s).?["+System.getProperty("line.separator")+"]"); Matcher m1 = p1.matcher(data1); Matcher m2 = p1.matcher(data2); while (m1.find()) { System.out.println("m1.start()="+m1.start()); System.out.println("m1.end()="+m1.end()); } while (m2.find()) { System.out.println("m2.start()="+m2.start()); System.out.println("m2.end()="+m2.end()); } } // TODO find '$' literal { System.out.println("4"); Pattern p1 = Pattern.compile("(?s).?[$]"); Matcher m1 = p1.matcher(data1); Matcher m2 = p1.matcher(data2); while (m1.find()) { System.out.println("m1.start()="+m1.start()); System.out.println("m1.end()="+m1.end()); } while (m2.find()) { System.out.println("m2.start()="+m2.start()); System.out.println("m2.end()="+m2.end()); } } / 1 m1.start()=0 m1.end()=4 m1.start()=4 m1.end()=8 m2.start()=0 m2.end()=4 m2.start()=4 m2.end()=8 2 m1.start()=0 m1.end()=7 m1.start()=7 m1.end()=7 m1.start()=8 m1.end()=8 m2.start()=0 m2.end()=11 m2.start()=11 m2.end()=11 3 m1.start()=0 m1.end()=4 m1.start()=4 m1.end()=8 m2.start()=0 m2.end()=4 m2.start()=4 m2.end()=8 4 / } @Test public void testRemoveFieldLoops() throws FileNotFoundException { final String endOfLineSymbol = System.getProperty("line.separator"); final String useMultiLines = "(?s)"; //! final String fieldDef1 = useMultiLines+"^[^\\\"][^,][,\|$\|"+endOfLineSymbol+"]"; /* \|d3 a4,\|__p1 / //!final String fieldDef1 = useMultiLines+"^[^\\\"].?[,\|$\|"+endOfLineSymbol+"]"; /* \| ,\|__p1 ---- b5,,d5 / //TODO handle empty cell first ^[,\|$\|"+endOfLineSymbol+"\|\\\n\|\\\Z] //TODO handle \\\Z //TODO define field separator // When a field is not started with a double quote, it does not have to be multi-lined. //TODO Need a haul for $ differing \\\n, see testIsDollarEndOfLineSame final String fieldDef1 = "^[^\\\"].?[,\|$\|"+endOfLineSymbol+"\|\\\n]"; /* ===== \| ,\|__p1 ---- b5,,d5 ===== / final String fieldDef2 = useMultiLines+"^[\\\"]([\\\"][\\\"]).?[\\\"]([\\\"][\\\"])[,\|$\|"+endOfLineSymbol+"]"; final String fieldDef3 = useMultiLines+"^[,\|$\|"+endOfLineSymbol+"]"; { System.out.println("\n\nStart 1 ... "); // This case is wrong. final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); boolean endOfFile = false; String tmp = data; while (!endOfFile) { Pattern p1 = Pattern.compile(fieldDef1); Matcher m1 = p1.matcher(tmp); if (m1.find()) { String field = tmp.substring(m1.start(),m1.end()); tmp = tmp.replaceFirst(fieldDef1,""); System.out.println("====="); System.out.println("\|"+field+"\|__p1"); System.out.println("----"); System.out.println(tmp); System.out.println("====="); //break; } else { Pattern p2 = Pattern.compile(fieldDef2); Matcher m2 = p2.matcher(tmp); if (m2.find()) { String field = tmp.substring(m2.start(),m2.end()); tmp = tmp.replaceFirst(fieldDef2,""); System.out.println("====="); System.out.println("\|"+field+"\|__p2"); System.out.println("----"); System.out.println(tmp); System.out.println("====="); //break; } else { break; } } } } } @Test public void testIsDollarEndOfLineSame () { String data1 = "a\nb"; String data2 = "a\n"; final String endOfLineSymbol = System.getProperty("line.separator"); for (String s: data1.split(endOfLineSymbol)) { System.out.println("\|"+s+"\|"); } System.out.println("====="); for (String s: data1.split("$")) { System.out.println("\|"+s+"\|"); } /* \|a\| \|b\| ===== \|a b\| / } @Test public void testMultilinesRegex() { { System.out.println("Start"); final String str1 = "a\nab\n \nc\n"; String input = str1; //Pattern p = Pattern.compile("(?s)^$"); //Pattern p = Pattern.compile("^[a]"); //Pattern p = Pattern.compile("(?s)^\\s\n"); Pattern p = Pattern.compile("(?s)^\\s+"); Matcher m = p.matcher(input); while (m.find()) { System.out.println(m.start()+" " +m.end()); } System.out.println(str1); } { System.out.println("Start"); final String str1 = "a m\nb b\n "; String input = str1; // \\s white space Pattern p = Pattern.compile("(?s)b\\sb"); Matcher m = p.matcher(input); while (m.find()) { System.out.println(m.start()+" " +m.end()); } System.out.println(str1); } { System.out.println("Start"); // find a pattern spanning multiple lines final String str1 = "a m\nb b\n "; String input = str1; // \\s white space Pattern p = Pattern.compile("(?s)m.b"); Matcher m = p.matcher(input); while (m.find()) { System.out.println(m.start()+" " +m.end()); String tmp = str1.substring(m.start(), m.end()); System.out.println(tmp); } //System.out.println(str1); } } @Test public void testMatchFields() throws FileNotFoundException { //final String useMultiLines = "(?s)"; final String useMultiLines = "(?s)"; //! final String fieldDef1 = "[^\"][^,][,\|$]"; //! final String fieldDef1 = "^[^\\\"][^,][,\|$]"; final String fieldDef1 = "[^\\\"][^,][,\|$]"; final String fieldDef2 = "[\\\"]([\\\"][\\\"]).?[\\\"]([\\\"][\\\"])[,\|$]"; // if a field does neither start with double quote nor start with a character that is not a double quote, // then the field is an empty string. final String fieldDef3 = "^[,\|$]"; { System.out.println("Start 1..."); final String data = "a,b,c c,d1\na2,b2,c2,d2"; Pattern p = Pattern.compile(useMultiLines+fieldDef1); String tmp = data; Matcher m = p.matcher(tmp); while (m.find()) { String field = tmp.substring(m.start(),m.end()); System.out.print(field +"\t"); } } { // no meaning System.out.println("\n\nStart 2 ..."); final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); Pattern p = Pattern.compile(useMultiLines+fieldDef1); String tmp = data; Matcher m = p.matcher(tmp); while (m.find()) { String field = tmp.substring(m.start(),m.end()); System.out.print(field +"\t"); } } { System.out.println("\n\nStart 3 ..."); final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); Pattern p = Pattern.compile(useMultiLines+fieldDef2); String tmp = data; Matcher m = p.matcher(tmp); while (m.find()) { String field = tmp.substring(m.start(),m.end()); System.out.print(field +"\t"); } } { System.out.println("\n\nStart 4 ... "); // This case is wrong. final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); Pattern p = Pattern.compile(useMultiLines+"("+fieldDef1+")\|("+fieldDef2+")"); String tmp = data; Matcher m = p.matcher(tmp); int count = 0; while (m.find()) { String field = tmp.substring(m.start(),m.end()); //System.out.print(field +"\t"); Pattern p1 = Pattern.compile(useMultiLines+fieldDef1); Matcher m1 = p.matcher(field); if (m1.find()) { System.out.print(field +"-p1\|"); } else { Pattern p2 = Pattern.compile(useMultiLines+fieldDef2); Matcher m2 = p2.matcher(field); if (m2.find()) { System.out.print(field +"-p2\|"); } else { System.out.print(field +"-p3\|"); } } count++; } System.out.println("count = "+count); } { System.out.println("\n\nStart 5 ... "); // This case is wrong. final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); Pattern p = Pattern.compile(useMultiLines+"("+fieldDef1+"\|"+fieldDef2+")"); String tmp = data; Matcher m = p.matcher(tmp); int count = 0; while (m.find()) { String field = tmp.substring(m.start(),m.end()); //System.out.print(field +"\t"); Pattern p1 = Pattern.compile(useMultiLines+fieldDef1); Matcher m1 = p.matcher(field); if (m1.find()) { System.out.print(field +"-p1\|"); } else { Pattern p2 = Pattern.compile(useMultiLines+fieldDef2); Matcher m2 = p2.matcher(field); if (m2.find()) { System.out.print(field +"-p2\|"); } else { System.out.print(field +"-p3\|"); } } count++; } System.out.println("count = "+count); } { System.out.println("\n\nStart 6 ... "); // This case is wrong. final String data = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); Pattern p = Pattern.compile(useMultiLines+""+fieldDef1+"\|"+fieldDef2+""); String tmp = data; Matcher m = p.matcher(tmp); int count = 0; while (m.find()) { String field = tmp.substring(m.start(),m.end()); //System.out.print(field +"\t"); Pattern p1 = Pattern.compile(useMultiLines+fieldDef1); Matcher m1 = p.matcher(field); if (m1.find()) { System.out.print(field +"-p1\|"); } else { Pattern p2 = Pattern.compile(useMultiLines+fieldDef2); Matcher m2 = p2.matcher(field); if (m2.find()) { System.out.print(field +"-p2\|"); } else { System.out.print(field +"-p3\|"); } } count++; } System.out.println("count = "+count); } // TODO remove trailing "," // TODO handle quote } @Test public void testReadFileToString() throws FileNotFoundException { String content = new Scanner(new File(this.getClass().getClassLoader().getResource("testfile1").getFile())).useDelimiter("\\Z").next(); System.out.println(content); } }
	Tiny CSV Reader VI. It is not a straight line 201507 It is not a linear process to get the program to pass the test data file. Some tasks are trivia, like reading a file to a string, testing multiple line regex, testing/using greedy/reluctant quantifiers etc. Put the test data in the source code file then you have to manually manipulate the escape sequence of characters. Some can be verified by brutal or deligent test, like the reluctant mode of a group need outer extra layer of brackets, unless you can memorize all the operator precedence. I still don't understand why we use this [^\\\"] for a literal that is not double quote -- it just works, the other ways around won't. It is also tricky that $, the dollar sign in multiple line mode is no longer a line separator (end of line), the austere literal(s) would be System.getProperty("line.separator"), but for convenience I just use \n. Mostly, the documentation tends to give you general ideas, highly abstraction (not exactly, it is hard to find theorem, equations and formula that are strict and leading deterministic results in a SDK), so may be it just tend to be brief. And the SDK version you use usually lags or over-shoots the documentation you are reading. If you go to the source code, unless you debug through every line with abundant leisure time, typically I give up at line twenty.
	Tiny CSV Reader VII. When it converges 201507 when the test passes for finding a literal appearing even times or odd times, I thought we are almost done. I suppose a record would just be, we just find a line separator without quote before it or a line separator with even counts of quote before it. But this 'or' condition caused some choas if you read/run test testParseRecords(). In a text book excercise of regular language (context free or not), you will define literal/alphabet strictly then apply the theorems and formula. But in this case, literal field separator and literal of record separator are all of wild card literal. I still didnot figure out the exact/correct regular grammar formula (symbol rules) but take a trial-error approach which is more of real life physics or engineering. The the analysis of testParseRecords() subdued us the conclusion that at either side of the 'or', the two conditions are not mutual exclusive, so when the matcher iterates through the input stream, the regex parser is confused so each findinng is not consuming just one condition but both condition. When I am writting a program, I am always considering I am designing a truth table. It always leads to fixed points. Sometimes, the truth table may be so big. So we may say if there is no theoretical foundation, well designed, logically sound requirments, it may not converge.
	Tiny CSV Reader VIII. Discussion 201507 Regular language is the fundamental base for understanding how computer programs work and how to write functioning computer programs. We take this chance to study, review some key techniques in regular expresion and partially solve a problem. Particularly for this task, there are still things open, to remove bordering quotes, to replace dual quotes with single quote, to do integrity check of the input file. For the last one, I suggest using a pre-allocate field-record grid to fill in parsed results so when the integrity check fails, the program will not halt abnormally and the users have a chance to review what went wrong. You can put your comments here https://github.com/wangzhikai/TinyCSVReader.