Refactor errors and update post draft.

13/ast.cpp

@@ -235,13 +235,13 @@ struct case_mappings {
 
     std::vector<instruction_ptr>& make_case_for(tag_type tag) {
         if(default_case)
-            throw type_error("attempted pattern match after catch-all");
+            throw compiler_error("attempted pattern match after catch-all");
         return defined_cases[tag];
     }
 
     std::vector<instruction_ptr>& make_default_case() {
         if(default_case)
-            throw type_error("attempted repeated use of catch-all");
+            throw compiler_error("attempted repeated use of catch-all");
         default_case.emplace(std::vector<instruction_ptr>());
         return *default_case;
     }
@@ -285,7 +285,7 @@ struct case_strategy_bool {
         if(!(cpat = dynamic_cast<pattern_constr*>(pt.get())) ||
                 (cpat->constr != "True" && cpat->constr != "False") ||
                 cpat->params.size() != 0)
-            throw type_error(
+            throw compiler_error(
                     "pattern cannot be converted to a boolean",
                     pt->loc);
         return cpat->constr == "True";
@@ -335,7 +335,7 @@ struct case_strategy_data {
     repr_type repr_from_pattern(const pattern_ptr& pt) {
         pattern_constr* cpat;
         if(!(cpat = dynamic_cast<pattern_constr*>(pt.get())))
-            throw type_error(
+            throw compiler_error(
                     "pattern cannot be interpreted as constructor.",
                     pt->loc);
         return std::make_pair(
@@ -398,7 +398,7 @@ void compile_case(const ast_case& node, const env_ptr& env, const type* type, st
         pattern_var* vpat;
         if((vpat = dynamic_cast<pattern_var*>(branch->pat.get()))) {
             if(cases.defined_cases_count() == strategy.case_count())
-                throw type_error("redundant catch-all pattern", branch->pat->loc);
+                throw compiler_error("redundant catch-all pattern", branch->pat->loc);
             auto& branch_into = cases.make_default_case();
             env_ptr new_env(new env_var(vpat->var, env));
             branch->expr->compile(new_env, branch_into);
@@ -412,7 +412,7 @@ void compile_case(const ast_case& node, const env_ptr& env, const type* type, st
 
     if(!(cases.defined_cases_count() == strategy.case_count() ||
                 cases.default_case_defined()))
-        throw type_error("incomplete patterns", node.loc);
+        throw compiler_error("incomplete patterns", node.loc);
 
     strategy.into_instructions(cases, into);
 }

13/definition.cpp

@@ -64,9 +64,9 @@ void definition_data::insert_constructors() const {
     type_ptr return_type(return_app);
     for(auto& var : vars) {
         if(var_set.find(var) != var_set.end())
-            throw std::runtime_error(
+            throw compiler_error(
                     std::string("type variable ") +
-                    var + std::string(" used twice in data type definition."));
+                    var + std::string(" used twice in data type definition."), loc);
         var_set.insert(var);
         return_app->arguments.push_back(type_ptr(new type_var(var)));
     }

13/error.cpp

@@ -1,19 +1,32 @@
 #include "error.hpp"
 
+const char* compiler_error::what() const noexcept {
+    return "an error occured while compiling the program";
+}
+
+void compiler_error::print_about(std::ostream& to) {
+    to << what() << ": ";
+    to << description << std::endl;
+}
+
+void compiler_error::print_location(std::ostream& to, parse_driver& drv, bool highlight) {
+    if(!loc) return;
+    to << "occuring on line " << loc->begin.line << ":" << std::endl;
+    drv.print_location(to, *loc, highlight);
+}
+
+void compiler_error::pretty_print(std::ostream& to, parse_driver& drv) {
+    print_about(to);
+    print_location(to, drv);
+}
+
 const char* type_error::what() const noexcept {
     return "an error occured while checking the types of the program";
 }
 
 void type_error::pretty_print(std::ostream& to, parse_driver& drv) {
-    to << "encountered error while typechecking program: ";
-    to << description << std::endl;
-
-    if(loc) {
-        to << "occuring on line " << loc->begin.line << ":" << std::endl;
-        to << std::endl << "```" << std::endl;
-        drv.print_highlighted_location(to, *loc);
-        to << "```" << std::endl << std::endl;
-    }
+    print_about(to);
+    print_location(to, drv, true);
 }
 
 void unification_error::pretty_print(std::ostream& to, parse_driver& drv, type_mgr& mgr) {

13/error.hpp

@@ -7,12 +7,26 @@
 
 using maybe_location = std::optional<yy::location>;
 
-struct type_error : std::exception {
+struct compiler_error : std::exception {
     std::string description;
+    maybe_location loc;
+
+    compiler_error(std::string d, maybe_location l = std::nullopt)
+        : description(std::move(d)), loc(std::move(l)) {}
+
+    const char* what() const noexcept override;
+
+    void print_about(std::ostream& to);
+    void print_location(std::ostream& to, parse_driver& drv, bool highlight = false);
+
+    void pretty_print(std::ostream& to, parse_driver& drv);
+};
+
+struct type_error : compiler_error {
     std::optional<yy::location> loc;
 
     type_error(std::string d, maybe_location l = std::nullopt)
-        : description(std::move(d)), loc(std::move(l)) {}
+        : compiler_error(std::move(d), std::move(l)) {}
 
     const char* what() const noexcept override;
     void pretty_print(std::ostream& to, parse_driver& drv);

13/main.cpp

@@ -20,7 +20,7 @@
 #include "llvm/Target/TargetMachine.h"
 
 void yy::parser::error(const yy::location& loc, const std::string& msg) {
-    std::cout << "An error occured: " << msg << std::endl;
+    std::cerr << "An error occured: " << msg << std::endl;
 }
 
 void prelude_types(definition_group& defs, type_env_ptr env) {
@@ -110,12 +110,12 @@ void output_llvm(llvm_context& ctx, const std::string& filename) {
         std::error_code ec;
         llvm::raw_fd_ostream file(filename, ec, llvm::sys::fs::F_None);
         if (ec) {
-            throw std::runtime_error("failed to open object file for writing");
+            throw compiler_error("failed to open object file for writing");
         } else {
             llvm::CodeGenFileType type = llvm::CGFT_ObjectFile;
             llvm::legacy::PassManager pm;
             if (targetMachine->addPassesToEmitFile(pm, file, NULL, type)) {
-                throw std::runtime_error("failed to add passes to pass manager");
+                throw compiler_error("failed to add passes to pass manager");
             } else {
                 pm.run(ctx.module);
                 file.close();
@@ -177,10 +177,11 @@ void gen_llvm(global_scope& scope) {
 int main(int argc, char** argv) {
     if(argc != 2) {
         std::cerr << "please enter a file to compile." << std::endl;
+        exit(1);
     }
     parse_driver driver(argv[1]);
     if(!driver.run_parse()) {
-        std::cerr << "failed to open file " << argv[1] << std::endl;
+        std::cerr << "failed to parse file " << argv[1] << std::endl;
         exit(1);
     }
 
@@ -207,7 +208,7 @@ int main(int argc, char** argv) {
         err.pretty_print(std::cerr, driver, mgr);
     } catch(type_error& err) {
         err.pretty_print(std::cerr, driver);
-    } catch(std::runtime_error& err) {
-        std::cerr << err.what() << std::endl;
+    } catch (compiler_error& err) {
+        err.pretty_print(std::cerr, driver);
     }
 }

13/parse_driver.cpp

@@ -5,8 +5,6 @@
 bool parse_driver::run_parse() {
     FILE* stream = fopen(file_name.c_str(), "r");
     if(!stream) return false;
-    string_stream = std::ostringstream();
-    file_offset = 0;
     line_offsets.push_back(0);
     yyscan_t scanner;
     yylex_init(&scanner);
@@ -29,27 +27,27 @@ void parse_driver::mark_line() {
 }
 
 size_t parse_driver::get_index(int line, int column) {
-    assert(line > 0);
-    assert(line <= line_offsets.size());
-    size_t file_offset = line_offsets[line-1];
-    file_offset += column - 1;
-    return file_offset;
+    assert(line > 0 && line <= line_offsets.size());
+    return line_offsets[line-1] + column - 1;
 }
 
 size_t parse_driver::get_line_end(int line) {
-    if(line > line_offsets.size()) return file_contents.size();
+    if(line == line_offsets.size()) return file_contents.size();
     return get_index(line+1, 1);
 }
 
-void parse_driver::print_highlighted_location(std::ostream& stream, const yy::location& loc) {
+void parse_driver::print_location(
+        std::ostream& stream,
+        const yy::location& loc,
+        bool highlight) {
     size_t print_start = get_index(loc.begin.line, 1);
     size_t highlight_start = get_index(loc.begin.line, loc.begin.column);
     size_t highlight_end = get_index(loc.end.line, loc.end.column);
     size_t print_end = get_line_end(loc.end.line);
     const char* content = file_contents.c_str();
     stream.write(content + print_start, highlight_start - print_start);
-    stream << "\033[4;31m";
+    if(highlight) stream << "\033[4;31m";
     stream.write(content + highlight_start, highlight_end - highlight_start);
-    stream << "\033[0m";
+    if(highlight) stream << "\033[0m";
     stream.write(content + highlight_end, print_end - highlight_end);
 }

13/parse_driver.hpp

@@ -14,13 +14,13 @@ void scanner_destroy(yyscan_t* scanner);
 struct parse_driver {
     std::string file_name;
     std::ostringstream string_stream;
+    std::string file_contents;
 
     yy::location location;
     size_t file_offset;
-
     std::vector<size_t> line_offsets;
+
     definition_group global_defs;
-    std::string file_contents;
 
     parse_driver(const std::string& file)
         : file_name(file), file_offset(0) {}
@@ -30,7 +30,10 @@ struct parse_driver {
     void mark_line();
     size_t get_index(int line, int column);
     size_t get_line_end(int line);
-    void print_highlighted_location(std::ostream& stream, const yy::location& loc);
+    void print_location(
+            std::ostream& stream,
+            const yy::location& loc,
+            bool highlight = true);
 };
 
 #define YY_DECL yy::parser::symbol_type yylex(yyscan_t yyscanner, parse_driver& drv)