add bi-token equalities (GTEQ, LTEQ)

diff --git a/lexer.c b/lexer.c
index 90982212f7c5be58ce6d76fe63d740c67e207c8d..1c56c67cf8a7d8838ead9e83b7f918fdcd3b561a 100644 (file)
--- a/lexer.c
+++ b/lexer.c
@@ -34,6 +34,7 @@ static Token makeToken(TokenKind kind, const char* lexeme) {
        t.kind = kind;
        t.lexeme = strdup(lexeme);
        t.intValue = 0;
+       t.floatValue = 0;
        return t;
 }
 
@@ -43,9 +44,70 @@ static Token makeNumberToken(int value, const char *lexeme) {
        t.kind = TK_NUMBER;
        t.intValue = value;
        t.lexeme = strdup(lexeme);
+       t.floatValue = 0.0;
        return t;
 }
 
+/* makeFloatToken: create token for floating literals */
+static Token makeFloatToken(double value, const char* lexeme) {
+       Token t;
+       t.kind = TK_FLOATLIT;
+       t.floatValue = value;
+       t.lexeme = strdup(lexeme);
+       t.intValue = 0;
+       return t;
+}
+
+/* lexNum: lexing numeric literals */
+static Token lexNum(void) {
+       char buffer[256];
+       int idx = 0;
+       bool hasDot = false;
+       bool hasExponent = false;
+
+       /* capture digits */
+       while (isdigit(g_currentChar) && idx < 255) {
+               buffer[idx++] = (char)g_currentChar;
+               advance();
+       }
+
+       /* check for dot */
+       if (g_currentChar == '.') {
+               hasDot = true;
+               buffer[idx++] = (char)g_currentChar;
+               advance();
+               while (isdigit(g_currentChar) && idx < 255) {
+                       buffer[idx++] = (char)g_currentChar;
+                       advance();
+               }
+       }
+
+       /* check for exponent */
+       if (g_currentChar == 'e' || g_currentChar == 'E') {
+               hasExponent = true;
+               buffer[idx++] = (char)g_currentChar;
+               advance();
+               if (g_currentChar == '+' || g_currentChar == '-') {
+                       buffer[idx++] = (char)g_currentChar;
+                       advance();
+               }
+               while (isdigit(g_currentChar) && idx <255) {
+                       buffer[idx++] = (char)g_currentChar;
+                       advance();
+               }
+       }
+
+       buffer[idx] = '\0';
+
+       if (hasDot || hasExponent) {
+               double value = strtod(buffer, NULL);
+               return makeFloatToken(value, buffer);
+       } else {
+               int value = atoi(buffer);
+               return makeNumberToken(value, buffer);
+       }
+}
+
 /* getNextToken: return next token from stream */
 Token getNextToken(void) {
        skipWhitespace();
@@ -65,7 +127,7 @@ Token getNextToken(void) {
                }
        }
 
-       /* Handle operators and punctuation */
+       /* handle operators and punctuation */
        if (g_currentChar == '=') {
                int nextChar = fgetc(g_input);
                if (nextChar == '=') {
@@ -79,6 +141,33 @@ Token getNextToken(void) {
                }
        }
 
+       /* dual equalities */
+       if (g_currentChar == '<') {
+               int nextChar = fgetc(g_input);
+               if (nextChar == '=') {
+                       advance();
+                       advance();
+                       return makeToken(TK_LTEQ, "<=");
+               } else {
+                       ungetc(nextChar, g_input);
+                       advance();
+                       return makeToken(TK_LT, "<");
+               }
+       }
+
+       if (g_currentChar == '>') {
+               int nextChar = fgetc(g_input);
+               if (nextChar == '=') {
+                       advance();
+                       advance();
+                       return makeToken(TK_GTEQ, ">=");
+               } else {
+                       ungetc(nextChar, g_input);
+                       advance();
+                       return makeToken(TK_GT, ">");
+               }
+       }
+
        if (g_currentChar == '+') { advance(); return makeToken(TK_PLUS, "+");  }
        if (g_currentChar == '-') { advance(); return makeToken(TK_MINUS, "-");  }
        if (g_currentChar == '*') { advance(); return makeToken(TK_STAR, "*");  }
@@ -88,19 +177,17 @@ Token getNextToken(void) {
        if (g_currentChar == '}') { advance(); return makeToken(TK_RBRACE, "}"); }
        if (g_currentChar == ';') { advance(); return makeToken(TK_SEMICOLON, ";"); }
        if (g_currentChar == ',') { advance(); return makeToken(TK_COMMA, ","); }
-       if (g_currentChar == '>') { advance(); return makeToken(TK_GT, ">"); }
+       //if (g_currentChar == '>') { advance(); return makeToken(TK_GT, ">"); }
+       //if (g_currentChar == '<') { advance(); return makeToken(TK_LT, "<"); }
 
        /* handle numeric literal */
        if (isdigit(g_currentChar)) {
-               char buffer[64];
-               int idx = 0;
-               while (isdigit(g_currentChar) && idx < 63) {
-                       buffer[idx++] = (char)g_currentChar;
-                       advance();
-               }
-               buffer[idx] = '\0';
-               int value = atoi(buffer);
-               return makeNumberToken(value, buffer);
+               return lexNum();
+       }
+       if (g_currentChar == '.') {
+               int next = fgetc(g_input);
+               ungetc(next, g_input);
+               if (isdigit(next)) return lexNum();
        }
 
        /* handle ident or keyword */

diff --git a/lexer.h b/lexer.h
index 4fc77dd0003847ab0fa06909a5226c6f0fc3b735..b12fb0d306f2f8091c83ffcff013ebe0abd6fcc0 100644 (file)
--- a/lexer.h
+++ b/lexer.h
@@ -17,7 +17,10 @@ typedef enum {
        TK_WHILE,       // `while`
        TK_IDENT,       // identifier
        TK_NUMBER,      // integer literal
+       TK_FLOATLIT,    // fp numeric literal
        TK_EQ,          // `==`
+       TK_GTEQ,        // `>=`
+       TK_LTEQ,        // `<=`
        TK_ASSIGN,      // `=`
        TK_PLUS,        // `+`
        TK_MINUS,       // `-`
@@ -28,8 +31,10 @@ typedef enum {
        TK_LBRACE,      // `{`
        TK_RBRACE,      // `}`
        TK_SEMICOLON,   // `;`
-       TK_COMMA,
+       TK_COMMA,       // `,`
+       TK_DOT,         // `.`
        TK_GT,          // `>`
+       TK_LT,          // `<`
        TK_EOF,         // EOF
        TK_UNKNOWN      // UNKNOWN
 } TokenKind;
@@ -39,6 +44,7 @@ typedef struct {
        TokenKind       kind;
        char*           lexeme;         // textual representation
        int             intValue;       // numeric literal value
+       double          floatValue;
 } Token;
 
 /* initialize the lexer; take source filename */

diff --git a/parser.c b/parser.c
index 0bac1fafa0db9f92e39f13a90596d7bbef2e52e7..e78f972c664f09d6da9336f3f036d61e06a57cd7 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -19,6 +19,7 @@ typedef enum {
        AST_EXPR_STMT,  // expresison statement
        AST_BINARY,     // bunary expression
        AST_NUM,        // numeric literal
+       AST_FLOAT,      // fp literal
        AST_IDENT,      // identifier
        AST_DECL,       // variable declaration
        AST_CALL        // function calls
@@ -35,6 +36,7 @@ struct ASTNode {
        char* funcName; // for function definitions
        ASTNode* funcBody; // body block
        int intValue;   // numeric literals
+       double floatValue;
        char* identName; // identifiers and operator string in binary nodes
        ASTNode** args; // array of argument nodes
        int argCount;   // number of arguments
@@ -63,6 +65,12 @@ static ASTNode* newNumNode(int value) {
        return node;
 }
 
+static ASTNode* newFloatNode(double value) {
+       ASTNode* node = newASTNode(AST_FLOAT);
+       node->floatValue = value;
+       return node;
+}
+
 static ASTNode* newIdentNode(const char* name) {
        ASTNode* node = newASTNode(AST_IDENT);
        node->identName = strdup(name);
@@ -251,7 +259,9 @@ static ASTNode* parseExpression(void) {
 /* equality := additive ( "==" additive )* */
 static ASTNode* parseEquality(void) {
        ASTNode* node = parseAdditive();
-       while (g_currentToken.kind == TK_EQ || g_currentToken.kind == TK_GT) {
+       while (g_currentToken.kind == TK_EQ || g_currentToken.kind == TK_GT
+                       || g_currentToken.kind == TK_LTEQ
+                       || g_currentToken.kind == TK_GTEQ) {
                TokenKind op = g_currentToken.kind;
                nextToken();
                ASTNode* rhs = parseAdditive();
@@ -259,6 +269,10 @@ static ASTNode* parseEquality(void) {
                        node = newBinaryNode(node, rhs, "==");
                else if (op == TK_GT) 
                        node = newBinaryNode(node, rhs, ">");
+               else if (op == TK_LTEQ)
+                       node = newBinaryNode(node, rhs, "<=");
+               else if (op == TK_GTEQ)
+                       node = newBinaryNode(node, rhs, ">=");
        }
        return node;
 }
@@ -345,6 +359,10 @@ static ASTNode* parseFactor(void) {
                nextToken();
                return node;
        }
+       if (g_currentToken.kind == TK_FLOATLIT) {
+               ASTNode* node = newFloatNode(g_currentToken.floatValue);
+               return node;
+       }
        fprintf(stderr, "Parse err: unexpected token '%s' in factor\n", g_currentToken.lexeme);
        exit(1);
        return NULL; // unreachable, but silences compiler warnings.
@@ -454,6 +472,10 @@ static void printAST(ASTNode* node, int indent) {
                        printIndent(indent);
                        printf("Number (%d)\n", node->intValue);
                        break;
+               case AST_FLOAT:
+                       printIndent(indent);
+                       printf("Float (%d)\n", node->floatValue);
+                       break;
                case AST_IDENT:
                        printIndent(indent);
                        printf("Identifier (%s)\n", node->identName);