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scanner.cpp
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scanner.cpp
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#include <fstream>
#include <iostream>
#include <variant>
#include <vector>
#include "types.h"
#include "nodes.h"
#include "general.h"
Scanner::Scanner(std::string sourceFilePath, bool* e) {
error = e;
sourceFile.open(sourceFilePath);
if (!sourceFile.is_open()) {
std::cout << "IO error: unable to open source file " << sourceFilePath << std::endl;
}
row = 1;
column = 1;
}
Scanner::~Scanner() {
sourceFile.close();
}
Token Scanner::nextToken() {
while (sourceFile.is_open()) {
c = sourceFile.get();
column++;
switch (c) {
case EOF:
return endfile;
case ';':
return endline;
case '+':
opVal = sum;
return add;
case '-':
opVal = subraction;
return add;
case '*':
opVal = multiplication;
return multi;
case '(':
return lbracet;
case ')':
return rbracet;
case '=':
opVal = equals;
return add;
case '&':
opVal = conjunction;
return add;
case '<':
opVal = less;
return add;
case '>':
opVal = greater;
return add;
case '!':
return negation;
case '.':
if (sourceFile.peek() == '.') {
sourceFile.get();
return dotdot;
} else {
std::cout << "Syntax error at" << locToStr(getLocation()) << ": keyword .. is missing second dot" << std::endl;
*error = true;
break;
}
case ':':
c = sourceFile.get();
if (c == '=') {
return assign;
} else {
sourceFile.unget();
return declare_type;
}
case '\n':
column = 1;
row++;
break;
}
if (c == '/') {
c = sourceFile.get();
switch (c) {
case '/':
// single comment, skip rest of line
while (c != '\n' && c != EOF) {
c = sourceFile.get();
}
if (c == EOF) {
return endfile;
}
sourceFile.unget();
column = 0;
row++;
break;
case '*': {
// multiline comment, skip until "*/"
int commentDepth = 1;
while (commentDepth > 0) {
c = sourceFile.get();
if (c == '*' && sourceFile.peek() == '/') {
commentDepth--;
sourceFile.get();
} else if (c == '/' && sourceFile.peek() == '*') {
commentDepth++;
sourceFile.get();
} else if (c == EOF) {
std::cout << "Syntax error at" << locToStr(getLocation()) << ": multiline comment missing closing tag" << std::endl;
*error = true;
break;
}
}
break;
}
default:
sourceFile.unget();
opVal = division;
return multi;
}
}
if (c == '\"') {
std::string stringBuild = "";
c = sourceFile.get();
while (c != '\"' && c != EOF) {
stringBuild += c;
c = sourceFile.get();
}
if (c == EOF) {
std::cout << "Syntax error at" << locToStr(getLocation()) << ": string missing closing quotation mark" << std::endl;
*error = true;
} else {
data = stringBuild;
typeVal = type_string;
return literal;
}
}
if (std::isdigit(c)) {
std::string numberBuild = "";
while (std::isdigit(c)) {
// number, DOES NOT RECOGNIZE FLOATS
numberBuild += c;
c = sourceFile.get();
}
data = std::stoi(numberBuild);
typeVal = type_int;
sourceFile.unget();
return literal;
}
if (std::isalpha(c)) {
std::string varBuild;
while (std::isalpha(c)) {
varBuild += c;
if (varBuild == "var") {
return declare_var;
}
if (varBuild == "if") {
return if_stmt;
}
if (varBuild == "for") {
return for_stmt;
}
if (varBuild == "in") {
if (sourceFile.peek() == 't') {
sourceFile.get();
typeVal = type_int;
return type;
} else {
return in_statement;
}
}
if (varBuild == "string") {
typeVal = type_string;
return type;
}
if (varBuild == "bool") {
typeVal = type_bool;
return type;
}
if (varBuild == "read") {
return read;
}
if (varBuild == "print") {
return print;
}
if (varBuild == "end") {
return end_statement;
}
if (varBuild == "true") {
data = true;
typeVal = type_bool;
return literal;
}
if (varBuild == "false") {
data = false;
typeVal = type_bool;
return literal;
}
if (varBuild == "do") {
return do_statement;
}
c = sourceFile.get();
}
if (varBuild != "") {
data = varBuild;
sourceFile.unget();
return id;
}
}
}
std::cout << "Syntax error at " << locToStr(getLocation()) << ": bad token match" << std::endl;
*error = true;
return endfile;
}
std::pair<int, int> Scanner::getLocation() {
return {column, row};
}
std::variant<std::string, int, bool> Scanner::getData() {
return data;
};
Operator Scanner::getOperator() {
return opVal;
};
Type Scanner::getType() {
return typeVal;
};