From fed70f3ac817ed4943a230cb901fcd65dc6fdd0c Mon Sep 17 00:00:00 2001
From: Maël Gassmann <mael.gassmann@students.bfh.ch>
Date: Fri, 11 Jun 2021 20:55:12 +0200
Subject: [~] First totaly functional Calculator, reorganised the files,
verified and added error messages
---
.../src/main/java/ch/bfh/CalculatorLexer.java | 106 ---------------------
calculator-java/src/main/java/ch/bfh/Main.java | 7 +-
calculator-java/src/main/java/ch/bfh/Token.java | 23 -----
.../java/ch/bfh/exceptions/LexerException.java | 5 -
.../java/ch/bfh/exceptions/ParserException.java | 5 -
.../main/java/ch/bfh/lexer/CalculatorLexer.java | 105 ++++++++++++++++++++
.../src/main/java/ch/bfh/lexer/LexerException.java | 5 +
.../src/main/java/ch/bfh/lexer/Token.java | 23 +++++
.../main/java/ch/bfh/parser/ExpressionParser.java | 36 ++++---
.../src/main/java/ch/bfh/parser/FactorParser.java | 15 +--
.../src/main/java/ch/bfh/parser/Parser.java | 7 +-
.../main/java/ch/bfh/parser/ParserException.java | 8 ++
.../main/java/ch/bfh/parser/StatementParser.java | 13 ++-
.../src/main/java/ch/bfh/parser/TermParser.java | 13 +--
14 files changed, 186 insertions(+), 185 deletions(-)
delete mode 100644 calculator-java/src/main/java/ch/bfh/CalculatorLexer.java
delete mode 100644 calculator-java/src/main/java/ch/bfh/Token.java
delete mode 100644 calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java
delete mode 100644 calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java
create mode 100644 calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java
create mode 100644 calculator-java/src/main/java/ch/bfh/lexer/LexerException.java
create mode 100644 calculator-java/src/main/java/ch/bfh/lexer/Token.java
create mode 100644 calculator-java/src/main/java/ch/bfh/parser/ParserException.java
(limited to 'calculator-java/src/main/java/ch/bfh')
diff --git a/calculator-java/src/main/java/ch/bfh/CalculatorLexer.java b/calculator-java/src/main/java/ch/bfh/CalculatorLexer.java
deleted file mode 100644
index 48d009e..0000000
--- a/calculator-java/src/main/java/ch/bfh/CalculatorLexer.java
+++ /dev/null
@@ -1,106 +0,0 @@
-package ch.bfh;
-import ch.bfh.exceptions.LexerException;
-
-// Lexer for classical arithmetic expressions with identifiers and assignments.
-// Scans a source string char by char.
-
-public class CalculatorLexer {
-
- private String src; // source string for lexical analysis
- private int idx; // current index in source
- private int len; // length of source
-
- public CalculatorLexer() { }
-
- public void initLexer(String source) {
- this.src = source;
- idx = 0;
- len = src.length();
- }
-
- // Consumes letters only and builds an identifier
- private String identifier() {
- StringBuffer s = new StringBuffer();
-
- do {
- s.append(src.charAt(idx));
- idx++;
- } while (idx < len && Character.isLetter(src.charAt(idx)));
- return s.toString();
- }
-
- // Consumes digits and convert integer part and decimal part
- // Convert characters using the formula
- // "3456.253" = [(((3+0)*10+4)*10+5)*10+6]+[0.1*2+0.01*5+0.001*3]
- private double number() throws LexerException {
- double v = 0; // accumulates the result
- double factor = 0.1; // factor for decimal part
-
- do { // integer part
- v = v * 10 + Character.digit(src.charAt(idx),30);
- idx++;
- } while (idx < len && Character.isDigit(src.charAt(idx)));
- if (idx < len && src.charAt(idx) == '.') { // decimal point
- idx++;
- if (idx < len && Character.isDigit(src.charAt(idx))) { // decimal part
- while (idx < len && Character.isDigit(src.charAt(idx))) {
- v = v + (factor * Character.digit(src.charAt(idx),30));
- factor = factor * 0.1;
- idx++;
- }
- }
- else throw new LexerException("Illegal number: decimal part missing");
- }
- return v;
- }
-
- // Skips blanks, tabs, newlines
- private void skip() {
- char c;
- while (idx < len) {
- c = src.charAt(idx);
- if (c==' ' || c=='\t' || c=='\n') idx++;
- else break;
- }
- }
-
- // returns next token
- public Token nextToken() throws LexerException {
- Token tok = new Token();
-
- skip();
- if (idx>=len) {
- tok.str="EOL";
- tok.type=Token.EOL;
- }
- else
- // is it a positive number?
- if (Character.isDigit(src.charAt(idx))) {
- tok.value = number();
- tok.type = Token.NUM;
- tok.str = Double.toString(tok.value);
- }
- else
- if (Character.isLetter(src.charAt(idx))) {
- tok.value = 0;
- tok.type = Token.ID;
- tok.str = identifier();
- if (tok.str.compareTo("let")==0) tok.type = Token.LET;
- if (tok.str.compareTo("exit")==0) tok.type = Token.END;
- }
- else {
- switch (src.charAt(idx)) {
- case '+': tok.type = Token.ADD; tok.str = "+"; break;
- case '-': tok.type = Token.SUB; tok.str = "-"; break;
- case '*': tok.type = Token.MUL; tok.str = "*"; break;
- case '/': tok.type = Token.DIV; tok.str = "/"; break;
- case '(': tok.type = Token.PAL; tok.str = "("; break;
- case ')': tok.type = Token.PAR; tok.str = ")"; break;
- case '=': tok.type = Token.EQU; tok.str = "="; break;
- default : throw new LexerException("Illegal Token: '" + src.charAt(idx) + "'");
- }
- idx++;
- }
- return tok;
- }
-}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/Main.java b/calculator-java/src/main/java/ch/bfh/Main.java
index 5dc8a91..ea01185 100644
--- a/calculator-java/src/main/java/ch/bfh/Main.java
+++ b/calculator-java/src/main/java/ch/bfh/Main.java
@@ -1,7 +1,8 @@
package ch.bfh;
+import ch.bfh.lexer.LexerException;
+import ch.bfh.parser.ParserException;
import ch.bfh.parser.StatementParser;
-
import java.util.Scanner;
public class Main {
@@ -16,8 +17,8 @@ public class Main {
try {
sp.parseStatement(expression);
- System.out.println(sp.getValue());
- } catch (Exception e) {
+ System.out.println("Result: " + sp.getValue());
+ } catch (LexerException | ParserException e) {
System.out.println(e.getMessage());
}
}
diff --git a/calculator-java/src/main/java/ch/bfh/Token.java b/calculator-java/src/main/java/ch/bfh/Token.java
deleted file mode 100644
index 93d4d02..0000000
--- a/calculator-java/src/main/java/ch/bfh/Token.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package ch.bfh;
-
-// Various Tokens for arithmetic expressions based on integers
-// with identifiers and assignments
-
-public class Token {
- public int type; // token type
- public double value; // numerical value for NUM
- public String str; // token string
-
- public static final int EOL=0; // End Of Line
- public static final int PAL=1; // Left Parenthesis
- public static final int PAR=2; // Right Parenthesis
- public static final int ADD=3; // operators
- public static final int SUB=4;
- public static final int MUL=5;
- public static final int DIV=6;
- public static final int NUM=7; // number
- public static final int EQU=8; // equal
- public static final int LET=9; // let
- public static final int ID=10; // identifier
- public static final int END=11; // exit
-}
diff --git a/calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java b/calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java
deleted file mode 100644
index 082beee..0000000
--- a/calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package ch.bfh.exceptions;
-
-public class LexerException extends RuntimeException {
- public LexerException(String s) { super(s); }
-}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java b/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java
deleted file mode 100644
index ca6d037..0000000
--- a/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package ch.bfh.exceptions;
-
-public class ParserException extends RuntimeException {
- public ParserException(String s) { super(s); }
-}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java b/calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java
new file mode 100644
index 0000000..0ba9535
--- /dev/null
+++ b/calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java
@@ -0,0 +1,105 @@
+package ch.bfh.lexer;
+
+// Lexer for classical arithmetic expressions with identifiers and assignments.
+// Scans a source string char by char.
+
+public class CalculatorLexer {
+
+ private String src; // source string for lexical analysis
+ private int idx; // current index in source
+ private int len; // length of source
+
+ public CalculatorLexer() { }
+
+ public void initLexer(String source) {
+ this.src = source;
+ idx = 0;
+ len = src.length();
+ }
+
+ // Consumes letters only and builds an identifier
+ private String identifier() {
+ StringBuffer s = new StringBuffer();
+
+ do {
+ s.append(src.charAt(idx));
+ idx++;
+ } while (idx < len && Character.isLetter(src.charAt(idx)));
+ return s.toString();
+ }
+
+ // Consumes digits and convert integer part and decimal part
+ // Convert characters using the formula
+ // "3456.253" = [(((3+0)*10+4)*10+5)*10+6]+[0.1*2+0.01*5+0.001*3]
+ private double number() throws LexerException {
+ double v = 0; // accumulates the result
+ double factor = 0.1; // factor for decimal part
+
+ do { // integer part
+ v = v * 10 + Character.digit(src.charAt(idx),30);
+ idx++;
+ } while (idx < len && Character.isDigit(src.charAt(idx)));
+ if (idx < len && src.charAt(idx) == '.') { // decimal point
+ idx++;
+ if (idx < len && Character.isDigit(src.charAt(idx))) { // decimal part
+ while (idx < len && Character.isDigit(src.charAt(idx))) {
+ v = v + (factor * Character.digit(src.charAt(idx),30));
+ factor = factor * 0.1;
+ idx++;
+ }
+ }
+ else throw new LexerException("Illegal number: decimal part missing");
+ }
+ return v;
+ }
+
+ // Skips blanks, tabs, newlines
+ private void skip() {
+ char c;
+ while (idx < len) {
+ c = src.charAt(idx);
+ if (c==' ' || c=='\t' || c=='\n') idx++;
+ else break;
+ }
+ }
+
+ // returns next token
+ public Token nextToken() throws LexerException {
+ Token tok = new Token();
+
+ skip();
+ if (idx>=len) {
+ tok.str="EOL";
+ tok.type=Token.EOL;
+ }
+ else
+ // is it a positive number?
+ if (Character.isDigit(src.charAt(idx))) {
+ tok.value = number();
+ tok.type = Token.NUM;
+ tok.str = Double.toString(tok.value);
+ }
+ else
+ if (Character.isLetter(src.charAt(idx))) {
+ tok.value = 0;
+ tok.type = Token.ID;
+ tok.str = identifier();
+ if (tok.str.compareTo("let")==0) tok.type = Token.LET;
+ if (tok.str.compareTo("exit")==0) tok.type = Token.END;
+ }
+ else {
+ switch (src.charAt(idx)) {
+ case '+': tok.type = Token.ADD; tok.str = "+"; break;
+ case '-': tok.type = Token.SUB; tok.str = "-"; break;
+ case '*': tok.type = Token.MUL; tok.str = "*"; break;
+ case '/': tok.type = Token.DIV; tok.str = "/"; break;
+ case '(': tok.type = Token.PAL; tok.str = "("; break;
+ case ')': tok.type = Token.PAR; tok.str = ")"; break;
+ case '=': tok.type = Token.EQU; tok.str = "="; break;
+ default : throw new LexerException("Illegal Token: '" + src.charAt(idx) + "'");
+ }
+ idx++;
+ }
+ return tok;
+ }
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/lexer/LexerException.java b/calculator-java/src/main/java/ch/bfh/lexer/LexerException.java
new file mode 100644
index 0000000..c5f8671
--- /dev/null
+++ b/calculator-java/src/main/java/ch/bfh/lexer/LexerException.java
@@ -0,0 +1,5 @@
+package ch.bfh.lexer;
+
+public class LexerException extends RuntimeException {
+ public LexerException(String s) { super(s); }
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/lexer/Token.java b/calculator-java/src/main/java/ch/bfh/lexer/Token.java
new file mode 100644
index 0000000..b021075
--- /dev/null
+++ b/calculator-java/src/main/java/ch/bfh/lexer/Token.java
@@ -0,0 +1,23 @@
+package ch.bfh.lexer;
+
+// Various Tokens for arithmetic expressions based on integers
+// with identifiers and assignments
+
+public class Token {
+ public int type; // token type
+ public double value; // numerical value for NUM
+ public String str; // token string
+
+ public static final int EOL=0;// // End Of Line
+ public static final int PAL=1;// // Left Parenthesis
+ public static final int PAR=2;// // Right Parenthesis
+ public static final int ADD=3;// // operators
+ public static final int SUB=4;//
+ public static final int MUL=5;
+ public static final int DIV=6;
+ public static final int NUM=7;// // number
+ public static final int EQU=8; // equal
+ public static final int LET=9; // let
+ public static final int ID=10;// // identifier
+ public static final int END=11; // exit
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
index 3ec0194..e68983b 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
@@ -1,22 +1,15 @@
package ch.bfh.parser;
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
-
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
import java.util.ArrayList;
-public class ExpressionParser extends Parser {
+class ExpressionParser extends Parser {
protected ArrayList<Parser> parsers = new ArrayList<>();
protected ArrayList<Token> ops = new ArrayList<>();
private boolean isParenthesised = false;
- public ExpressionParser(CalculatorLexer cl) {
- this.cl = cl;
- parse();
- }
-
protected ExpressionParser(CalculatorLexer cl, Token lastToken, boolean isParenthesised) {
this.cl = cl;
this.lastToken = lastToken;
@@ -31,8 +24,8 @@ public class ExpressionParser extends Parser {
token = lastToken;
else
token = cl.nextToken();
- Parser l = null;
- Parser r = null; // left and right expressions
+ TermParser l = null;
+ TermParser r = null; // left and right Terms
Token op = null; // operation of the current l and right expressions
loop:
@@ -48,9 +41,9 @@ public class ExpressionParser extends Parser {
op = token;
this.ops.add(op);
}else if (l == null)
- throw new ParserException("Factor cannot start with '+'.");
+ throw new ParserException("Redundant use of '+' is forbidden.");
else
- throw new ParserException("Invalid use of '+' was found in the Expression.");
+ throw new ParserException(token, "repetition of operator -> a term was expected.");
break;
case Token.SUB:
if (l != null && op == null) { // if the '-' sign is between two term (op)
@@ -82,14 +75,19 @@ public class ExpressionParser extends Parser {
break loop;
} else
throw new ParserException("No matching opening parenthesis were found.");
- default:
- //TODO - Replace default by each individual case
- throw new ParserException("Malformed Expression.");
+ case Token.MUL:
+ case Token.DIV:
+ throw new ParserException(token,"a term was expected.");
+ case Token.EQU:
+ case Token.LET:
+ throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+ case Token.END:
+ throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
}
token = cl.nextToken();
}
if (op != null && r == null)
- throw new ParserException("Missing expression after last operation '"+op.str+"'");
+ throw new ParserException("Missing term after the last operator '"+op.str+"'.");
}
@Override
@@ -111,4 +109,4 @@ public class ExpressionParser extends Parser {
}
return result;
}
-}
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
index 8bb5ef7..fd54cf4 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
@@ -1,8 +1,7 @@
package ch.bfh.parser;
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
class FactorParser extends Parser {
@@ -72,9 +71,11 @@ class FactorParser extends Parser {
lastToken = token;
else throw new ParserException("Missing expression before closing the parenthesis.");
break loop;
- default:
- //TODO - Replace default by each individual case
- throw new ParserException("Malformed Expression.");
+ case Token.EQU:
+ case Token.LET:
+ throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+ case Token.END:
+ throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
}
token = cl.nextToken();
}
@@ -91,4 +92,4 @@ class FactorParser extends Parser {
return value * (-1);
return value;
}
-}
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/Parser.java b/calculator-java/src/main/java/ch/bfh/parser/Parser.java
index 333b942..6a03fe1 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/Parser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/Parser.java
@@ -1,14 +1,13 @@
package ch.bfh.parser;
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
import java.util.HashMap;
import java.util.Map;
abstract class Parser{
- protected static Map<String, ExpressionParser> variables = new HashMap<>(); //'Persisted' Expressions when 'let' token was specified
+ protected static Map<String, ExpressionParser> variables = new HashMap<>(); //Persisted Expressions aka variables
protected CalculatorLexer cl;
protected Token lastToken;
diff --git a/calculator-java/src/main/java/ch/bfh/parser/ParserException.java b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java
new file mode 100644
index 0000000..a85e3b2
--- /dev/null
+++ b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java
@@ -0,0 +1,8 @@
+package ch.bfh.parser;
+
+import ch.bfh.lexer.Token;
+
+public class ParserException extends RuntimeException {
+ public ParserException(String s) { super(s); }
+ public ParserException(Token token, String s) { super("Last read token: '"+token.str+"', "+s); }
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
index c85398b..482ef34 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
@@ -1,8 +1,7 @@
package ch.bfh.parser;
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
public class StatementParser extends Parser{
@@ -27,15 +26,15 @@ public class StatementParser extends Parser{
switch (token.type) {
case Token.LET:
if (lastToken != null)
- throw new ParserException("The keyword 'let' cannot be placed anywhere else than at the beginning of an expression.");
+ throw new ParserException("The keyword 'let' can only be placed at the beginning of an expression.");
break;
case Token.EQU:
if (lastToken == null || lastToken.type != Token.LET || variableName == null)
- throw new ParserException("The inputted token '=' can only be placed in a variable declaration context (let variable = Expression).");
+ throw new ParserException("The token '=' can only be placed in a variable declaration context (let var = Expression).");
break;
case Token.END:
if (lastToken != null)
- throw new ParserException("The keyword 'exit' cannot be placed anywhere else than at the beginning of an expression.");
+ throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
else
System.exit(0);
case Token.ID:
@@ -58,7 +57,7 @@ public class StatementParser extends Parser{
if (lastToken == null)
return;
if (lastToken.type == Token.LET || lastToken.type == Token.EQU)
- throw new ParserException("Incomplete variable declaration");
+ throw new ParserException("Incomplete variable declaration. Expected: let var = Expression.");
}
@Override
diff --git a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
index 9a97659..9e49fa8 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
@@ -1,8 +1,7 @@
package ch.bfh.parser;
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
class TermParser extends ExpressionParser {
@@ -61,9 +60,11 @@ class TermParser extends ExpressionParser {
case Token.PAR: // Going as high as possible --> possibly the end of an expression created by a Factor :)
lastToken = token;
break loop;
- default:
- //TODO - Replace default by each individual case
- throw new ParserException("Malformed Expression.");
+ case Token.EQU:
+ case Token.LET:
+ throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+ case Token.END:
+ throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
}
token = cl.nextToken();
}
--
cgit v1.2.3