From 3444b5b58a78c12a79365bb35e54cfa029fccd99 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Tue, 12 Oct 2021 10:53:20 +0200
Subject: Add error dispatch procedure

---
 src/bootstrap/errors.c | 33 ++++++++++++++++++++++++++++++
 src/bootstrap/lexer.c  | 52 ++++++++++++++++++++++++++---------------------
 src/bootstrap/main.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 116 insertions(+), 24 deletions(-)
 create mode 100644 src/bootstrap/errors.c

diff --git a/src/bootstrap/errors.c b/src/bootstrap/errors.c
new file mode 100644
index 0000000..fcb629a
--- /dev/null
+++ b/src/bootstrap/errors.c
@@ -0,0 +1,33 @@
+typedef enum ErrorType {
+    ERR_TYPE_LEXER,
+    ERR_TYPE_PARSER,
+    ERR_TYPE_RUNTIME,
+} ErrorType;
+
+typedef enum ErrorValue {
+    ERR_UNKNOWN = 0,
+    ERR_UNMATCHED_STRING,
+} ErrorValue;
+
+typedef struct Error {
+    ErrorType type;
+    ErrorValue value;
+    size_t line;
+    size_t col;
+} Error;
+
+static const char* error_msgs[] = {
+    [ERR_UNKNOWN] = "error: something unexpected happened",
+    [ERR_UNMATCHED_STRING] = "error: unmatched string delimiter",
+};
+
+#define ERR_MAX_NUMBER 16
+static Error errors[ERR_MAX_NUMBER];
+static size_t errors_n = 0;
+
+void
+error_push(Error error) {
+    if (errors_n < ERR_MAX_NUMBER) {
+        errors[errors_n++] = error;
+    }
+}
diff --git a/src/bootstrap/lexer.c b/src/bootstrap/lexer.c
index 1add4dc..49431d0 100644
--- a/src/bootstrap/lexer.c
+++ b/src/bootstrap/lexer.c
@@ -134,6 +134,28 @@ skip_whitespace(Scanner *scanner) {
     }
 }
 
+bool
+is_delimiter(char c) {
+    switch (c) {
+        case EOF:
+        case '\0':
+        case ';':
+        case '"':
+        case '\'':
+        case '(':
+        case ')':
+        case ' ':
+        case '\f':
+        case '\n':
+        case '\r':
+        case '\t':
+        case '\v': {
+            return true;
+        } break;
+    }
+    return false;
+}
+
 TokenType
 find_primitive_type(StringView value) {
     bool is_fixnum = true;
@@ -159,28 +181,6 @@ find_primitive_type(StringView value) {
     return TOKEN_SYMBOL;
 }
 
-bool
-is_delimiter(char c) {
-    switch (c) {
-        case EOF:
-        case '\0':
-        case ';':
-        case '"':
-        case '\'':
-        case '(':
-        case ')':
-        case ' ':
-        case '\f':
-        case '\n':
-        case '\r':
-        case '\t':
-        case '\v': {
-            return true;
-        } break;
-    }
-    return false;
-}
-
 Tokens
 tokenize(const StringView *sv) {
     Tokens tokens = (Tokens){0};
@@ -214,7 +214,13 @@ tokenize(const StringView *sv) {
                     n++;
                 }
                 if (!found) {
-                    // TODO: Report error: couldn't find the closing quotes.
+                    error_push((Error){
+                            .type = ERR_TYPE_LEXER,
+                            .value = ERR_UNMATCHED_STRING,
+                            .line = line,
+                            .col = col,
+                    });
+                    return tokens;
                 }
                 Token token =  (Token){
                     .value = (StringView){
diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index 113ee48..dadc887 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -5,11 +5,18 @@
 
 #include "string_view.c"
 #include "read_line.c"
+#include "errors.c"
 #include "lexer.c"
 
 void
 process_source(const StringView *source) {
     Tokens tokens = tokenize(source);
+    if (errors_n != 0) {
+        if (tokens.buf != NULL) {
+            free(tokens.buf);
+        }
+        return;
+    }
 
     // Print tokens.
     for (size_t i = 0; i < tokens.size; i++) {
@@ -17,7 +24,9 @@ process_source(const StringView *source) {
         print_token(tok);
     }
 
-    free(tokens.buf);
+    if (tokens.buf != NULL) {
+        free(tokens.buf);
+    }
 }
 
 #define REPL_PROMPT "bdl> "
@@ -32,6 +41,24 @@ run_repl(void) {
             return;
         }
         process_source(&sv);
+
+        // Check if there were any errors.
+        if (errors_n != 0) {
+            for (size_t i = 0; i < errors_n; i++) {
+                Error err = errors[i];
+                for (size_t j = 0; j < err.col + sizeof(REPL_PROMPT) - 2; j++) {
+                    putchar(' ');
+                }
+                printf("|\n");
+                for (size_t j = 0; j < err.col + sizeof(REPL_PROMPT) - 2; j++) {
+                    putchar(' ');
+                }
+                printf("%s\n", error_msgs[err.value]);
+            }
+            errors_n = 0;
+            continue;
+        }
+
         if (sv.n != 0) {
             printf("\n");
         }
@@ -62,6 +89,19 @@ run_file(char *file_name) {
 
     process_source(&sv);
 
+    // Check if there were any errors.
+    if (errors_n != 0) {
+        for (size_t i = 0; i < errors_n; i++) {
+            Error err = errors[i];
+            printf("%s", file_name);
+            if (err.line != 0) {
+                printf(":%ld:%ld", err.line, err.col);
+            }
+            printf("%s\n", error_msgs[err.value]);
+        }
+        errors_n = 0;
+    }
+
     free(source);
     fclose(file);
 }
@@ -91,6 +131,19 @@ run_stdin(void) {
 
     process_source(&sv);
 
+    // Check if there were any errors.
+    if (errors_n != 0) {
+        for (size_t i = 0; i < errors_n; i++) {
+            Error err = errors[i];
+            printf("stdin");
+            if (err.line != 0) {
+                printf(":%ld:%ld: ", err.line, err.col);
+            }
+            printf("%s\n", error_msgs[err.value]);
+        }
+        errors_n = 0;
+    }
+
     free(source);
 }
 
-- 
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