Exercise 2/C/Lexer.c

@@ -0,0 +1,31 @@
+#include "Lexer.h"
+
+int start(char* src) {
+    // if (src != NULL) {
+    //     return _GET_NEXT_CHARACTER_;
+    // } else {
+    //     return _STOP_;
+    // }
+
+    return _STOP_; // placeholder
+}
+
+int getNextCharacter() {
+    return _STOP_; // placeholder
+}
+
+int readIdentifier() {
+    return _STOP_; // placeholder
+}
+
+int readNumLit() {
+    return _STOP_; // placeholder
+}
+
+int readOperator() {
+    return _STOP_; // placeholder
+}
+
+int readPunctuation() {
+    return _STOP_; // placeholder
+}

Exercise 2/C/Lexer.h

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+/* symbols */
+#define _LETTER_ 1
+#define _DIGIT_ 2
+#define _OPERATOR_ 3
+#define _PUNCTUATION_ 4
+#define _END_OF_LINE_ 5
+#define _UNKNOWN_ 10
+
+/* state */
+#define _START_ 100
+#define _GET_NEXT_CHARACTER_ 110
+#define _READ_IDENTIFIER_ 120
+#define _READ_NUM_LIT_ 130
+#define _READ_OPERATOR_ 140
+#define _READ_PUNCTUATION_ 150
+#define _STOP_ 999
+#define _ERROR_ 1000
+
+/* functions */
+int start(char*);
+int getNextCharacter();
+int readIdentifier();
+int readNumLit();
+int readOperator();
+int readPunctuation();
+int main();

Exercise 2/C/TestLexer.c

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+#include <stdio.h>
+#include "Lexer.h"
+#include "Lexer.c"
+
+int main() {
+    char* sourcecode = "Hello World the second - I coded this before. So yeah, FOXES ARE SUPERIOR.\nBut the professor wants us to write the following: \"index = 2 * count + 42;\"\n\n";
+    printf(sourcecode);
+
+    int lexer_state = _START_;
+    do {
+        switch (lexer_state) {
+            case _START_:
+                lexer_state = start(sourcecode);
+                break;
+            case _GET_NEXT_CHARACTER_:
+                lexer_state = getNextCharacter();
+                break;
+            case _READ_IDENTIFIER_:
+                lexer_state = readIdentifier();
+                break;
+            case _READ_NUM_LIT_:
+                lexer_state = readNumLit();
+                break;
+            case _READ_OPERATOR_:
+                lexer_state = readOperator();
+                break;
+            case _READ_PUNCTUATION_:
+                lexer_state = readPunctuation();
+                break;
+            default: lexer_state = _ERROR_;
+        }
+    } while (lexer_state != _STOP_);
+
+    // printf("Lexer exited with code ");
+    // printf(lexer_state);
+
+    return 0;
+}

Exercise 3/Lexer.c

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+#include "Lexer.h"
+
+int start(char* src) {
+    if (src != 0 && src != '\0') {      // checking if the string is empty or invalid
+        return _GET_NEXT_CHARACTER_;
+    }
+    return _STOP_;
+}
+
+int getNextCharacter(char* src) {
+    return _STOP_;                      // placeholder
+}
+
+int readIdentifier(char* src) {
+    return _STOP_;                      // placeholder
+}
+
+int readNumLit(char* src) {
+    return _STOP_;                      // placeholder
+}
+
+int readOperator(char* src) {
+    return _STOP_;                      // placeholder
+}
+
+int readPunctuation(char* src) {
+    return _STOP_;                      // placeholder
+}

Exercise 3/Lexer.h

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+/* symbols */
+#define _LETTER_ 1
+#define _DIGIT_ 2
+#define _OPERATOR_ 3
+#define _PUNCTUATION_ 4
+#define _END_OF_LINE_ 5
+#define _UNKNOWN_ 10
+
+/* state */
+#define _START_ 100
+#define _GET_NEXT_CHARACTER_ 110
+#define _READ_IDENTIFIER_ 120
+#define _READ_NUM_LIT_ 130
+#define _READ_OPERATOR_ 140
+#define _READ_PUNCTUATION_ 150
+#define _STOP_ 999
+#define _ERROR_ 1000
+
+/* functions */
+int start(char*);
+int getNextCharacter(char*);
+int readIdentifier(char*);
+int readNumLit(char*);
+int readOperator(char*);
+int readPunctuation(char*);
+int main();

Exercise 3/TestLexer.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include "Lexer.h"
+#include "Lexer.c"
+
+int main() {
+    // variables
+    char* sourcecode = "index = 2 * count + 42;";               // input string
+    int lexer_state = _START_;                                  // int var for the state machine
+
+    // checking var values
+    printf(sourcecode);                                         // printing the input string to check it
+
+    // main loop
+    do {
+        switch (lexer_state) {                                  // state machine starts here
+            case _START_:
+                lexer_state = start(sourcecode);
+                break;
+            case _GET_NEXT_CHARACTER_:
+                lexer_state = getNextCharacter(sourcecode);
+                break;
+            case _READ_IDENTIFIER_:
+                lexer_state = readIdentifier(sourcecode);
+                break;
+            case _READ_NUM_LIT_:
+                lexer_state = readNumLit(sourcecode);
+                break;
+            case _READ_OPERATOR_:
+                lexer_state = readOperator(sourcecode);
+                break;
+            case _READ_PUNCTUATION_:
+                lexer_state = readPunctuation(sourcecode);
+                break;
+            default: lexer_state = _ERROR_;
+        }
+    } while (lexer_state != _STOP_);                            // state machine ends here
+
+    // printf("Lexer exited with code ");
+    // printf(lexer_state);
+
+    return 0;
+}