error: improved parser error reporting

now it shows a visual indicator '^' pointing to the position of the
error, in the line after the error message. should be helpful for users
writing templates, if any.

3 files changed, 132 insertions, 61 deletions

diff --git a/tests/check_error.c b/tests/check_error.c
index 8818b00..a954095 100644
--- a/tests/check_error.c
+++ b/tests/check_error.c
@@ -49,21 +49,27 @@ test_error_parser(void **state)
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 3, position 2: chunda");
+        "asd 10\nError occurred near line 3, position 2:\n"
+        "chunda\n"
+        " ^");
     blogc_error_free(error);
     a = "bola\nguda\nchunda";
     error = blogc_error_parser(1, a, strlen(a), 11, "asd %d", 10);
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 3, position 2: chunda");
+        "asd 10\nError occurred near line 3, position 2:\n"
+        "chunda\n"
+        " ^");
     blogc_error_free(error);
     a = "bola\nguda\nchunda";
     error = blogc_error_parser(1, a, strlen(a), 0, "asd %d", 10);
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 1, position 1: bola");
+        "asd 10\nError occurred near line 1, position 1:\n"
+        "bola\n"
+        "^");
     blogc_error_free(error);
     a = "";
     error = blogc_error_parser(1, a, strlen(a), 0, "asd %d", 10);
@@ -82,21 +88,27 @@ test_error_parser_crlf(void **state)
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 3, position 2: chunda");
+        "asd 10\nError occurred near line 3, position 2:\n"
+        "chunda\n"
+        " ^");
     blogc_error_free(error);
     a = "bola\r\nguda\r\nchunda";
     error = blogc_error_parser(1, a, strlen(a), 13, "asd %d", 10);
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 3, position 2: chunda");
+        "asd 10\nError occurred near line 3, position 2:\n"
+        "chunda\n"
+        " ^");
     blogc_error_free(error);
     a = "bola\r\nguda\r\nchunda";
     error = blogc_error_parser(1, a, strlen(a), 0, "asd %d", 10);
     assert_non_null(error);
     assert_int_equal(error->type, 1);
     assert_string_equal(error->msg,
-        "asd 10\nError occurred near line 1, position 1: bola");
+        "asd 10\nError occurred near line 1, position 1:\n"
+        "bola\n"
+        "^");
     blogc_error_free(error);
 }
 
diff --git a/tests/check_source_parser.c b/tests/check_source_parser.c
index d94dc70..2dcaad6 100644
--- a/tests/check_source_parser.c
+++ b/tests/check_source_parser.c
@@ -220,7 +220,9 @@ test_source_parse_config_invalid_key(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Can't find a configuration key or the content separator.\n"
-        "Error occurred near line 1, position 1: bola: guda");
+        "Error occurred near line 1, position 1:\n"
+        "bola: guda\n"
+        "^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -236,7 +238,9 @@ test_source_parse_config_no_key(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Invalid configuration key.\n"
-        "Error occurred near line 1, position 4: BOLa");
+        "Error occurred near line 1, position 4:\n"
+        "BOLa\n"
+        "   ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -252,7 +256,9 @@ test_source_parse_config_no_key2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Your last configuration key is missing ':' and the value\n"
-        "Error occurred near line 1, position 5: BOLA");
+        "Error occurred near line 1, position 5:\n"
+        "BOLA\n"
+        "    ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -269,7 +275,9 @@ test_source_parse_config_no_value(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Configuration value not provided for 'BOLA'.\n"
-        "Error occurred near line 1, position 6: BOLA:");
+        "Error occurred near line 1, position 6:\n"
+        "BOLA:\n"
+        "     ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -286,7 +294,9 @@ test_source_parse_config_no_value2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Configuration value not provided for 'BOLA'.\n"
-        "Error occurred near line 1, position 6: BOLA:");
+        "Error occurred near line 1, position 6:\n"
+        "BOLA:\n"
+        "     ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -490,7 +500,9 @@ test_source_parse_config_value_no_line_ending(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "No line ending after the configuration value for 'BOLA'.\n"
-        "Error occurred near line 1, position 10: BOLA: asd");
+        "Error occurred near line 1, position 10:\n"
+        "BOLA: asd\n"
+        "         ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
@@ -507,7 +519,9 @@ test_source_parse_invalid_separator(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_SOURCE_PARSER);
     assert_string_equal(err->msg,
         "Invalid content separator. Must be more than one '-' characters.\n"
-        "Error occurred near line 2, position 4: ---#");
+        "Error occurred near line 2, position 4:\n"
+        "---#\n"
+        "   ^");
     blogc_error_free(err);
     sb_trie_free(source);
 }
diff --git a/tests/check_template_parser.c b/tests/check_template_parser.c
index d2d5e8d..8264ffa 100644
--- a/tests/check_template_parser.c
+++ b/tests/check_template_parser.c
@@ -455,7 +455,9 @@ test_template_parse_invalid_block_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Must begin with lowercase letter.\n"
-        "Error occurred near line 1, position 4: {% ASD %}");
+        "Error occurred near line 1, position 4:\n"
+        "{% ASD %}\n"
+        "   ^");
     blogc_error_free(err);
     a = "{%-- block entry %}\n";
     err = NULL;
@@ -465,7 +467,9 @@ test_template_parse_invalid_block_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Duplicated whitespace cleaner before statement.\n"
-        "Error occurred near line 1, position 4: {%-- block entry %}");
+        "Error occurred near line 1, position 4:\n"
+        "{%-- block entry %}\n"
+        "   ^");
     blogc_error_free(err);
     a = "{% block entry --%}\n";
     err = NULL;
@@ -475,7 +479,9 @@ test_template_parse_invalid_block_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Duplicated whitespace cleaner after statement.\n"
-        "Error occurred near line 1, position 17: {% block entry --%}");
+        "Error occurred near line 1, position 17:\n"
+        "{% block entry --%}\n"
+        "                ^");
     blogc_error_free(err);
 }
 
@@ -493,7 +499,9 @@ test_template_parse_invalid_block_nested(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Blocks can't be nested.\n"
-        "Error occurred near line 2, position 9: {% block listing %}");
+        "Error occurred near line 2, position 9:\n"
+        "{% block listing %}\n"
+        "        ^");
     blogc_error_free(err);
 }
 
@@ -511,7 +519,9 @@ test_template_parse_invalid_foreach_nested(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "'foreach' statements can't be nested.\n"
-        "Error occurred near line 2, position 11: {% foreach B %}");
+        "Error occurred near line 2, position 11:\n"
+        "{% foreach B %}\n"
+        "          ^");
     blogc_error_free(err);
 }
 
@@ -527,7 +537,9 @@ test_template_parse_invalid_block_not_open(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "'endblock' statement without an open 'block' statement.\n"
-        "Error occurred near line 1, position 12: {% endblock %}");
+        "Error occurred near line 1, position 12:\n"
+        "{% endblock %}\n"
+        "           ^");
     blogc_error_free(err);
 }
 
@@ -543,8 +555,9 @@ test_template_parse_invalid_endif_not_open(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "'endif' statement without an open 'if', 'ifdef' or 'ifndef' statement.\n"
-        "Error occurred near line 1, position 28: "
-        "{% block listing %}{% endif %}{% endblock %}");
+        "Error occurred near line 1, position 28:\n"
+        "{% block listing %}{% endif %}{% endblock %}\n"
+        "                           ^");
     blogc_error_free(err);
 }
 
@@ -560,7 +573,9 @@ test_template_parse_invalid_endforeach_not_open(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "'endforeach' statement without an open 'foreach' statement.\n"
-        "Error occurred near line 1, position 14: {% endforeach %}");
+        "Error occurred near line 1, position 14:\n"
+        "{% endforeach %}\n"
+        "             ^");
     blogc_error_free(err);
 }
 
@@ -577,7 +592,9 @@ test_template_parse_invalid_block_name(void **state)
     assert_string_equal(err->msg,
         "Invalid statement type: Allowed types are: 'block', 'endblock', 'ifdef', "
         "'ifndef', 'else', 'endif', 'foreach' and 'endforeach'.\n"
-        "Error occurred near line 1, position 10: {% chunda %}");
+        "Error occurred near line 1, position 10:\n"
+        "{% chunda %}\n"
+        "         ^");
     blogc_error_free(err);
 }
 
@@ -593,7 +610,9 @@ test_template_parse_invalid_block_type_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid block syntax. Must begin with lowercase letter.\n"
-        "Error occurred near line 1, position 10: {% block ENTRY %}");
+        "Error occurred near line 1, position 10:\n"
+        "{% block ENTRY %}\n"
+        "         ^");
     blogc_error_free(err);
 }
 
@@ -609,7 +628,9 @@ test_template_parse_invalid_block_type(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid block type. Allowed types are: 'entry', 'listing' and 'listing_once'.\n"
-        "Error occurred near line 1, position 16: {% block chunda %}");
+        "Error occurred near line 1, position 16:\n"
+        "{% block chunda %}\n"
+        "               ^");
     blogc_error_free(err);
 }
 
@@ -625,8 +646,9 @@ test_template_parse_invalid_ifdef_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 27: "
-        "{% block entry %}{% ifdef guda %}");
+        "Error occurred near line 1, position 27:\n"
+        "{% block entry %}{% ifdef guda %}\n"
+        "                          ^");
     blogc_error_free(err);
 }
 
@@ -642,8 +664,9 @@ test_template_parse_invalid_foreach_start(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid foreach variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 29: "
-        "{% block entry %}{% foreach guda %}");
+        "Error occurred near line 1, position 29:\n"
+        "{% block entry %}{% foreach guda %}\n"
+        "                            ^");
     blogc_error_free(err);
 }
 
@@ -659,8 +682,9 @@ test_template_parse_invalid_ifdef_variable(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must be uppercase letter, number or '_'.\n"
-        "Error occurred near line 1, position 28: "
-        "{% block entry %}{% ifdef BoLA %}");
+        "Error occurred near line 1, position 28:\n"
+        "{% block entry %}{% ifdef BoLA %}\n"
+        "                           ^");
     blogc_error_free(err);
 }
 
@@ -676,8 +700,9 @@ test_template_parse_invalid_ifdef_variable2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 27: "
-        "{% block entry %}{% ifdef 0123 %}");
+        "Error occurred near line 1, position 27:\n"
+        "{% block entry %}{% ifdef 0123 %}\n"
+        "                          ^");
     blogc_error_free(err);
 }
 
@@ -693,8 +718,9 @@ test_template_parse_invalid_foreach_variable(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid foreach variable name. Must be uppercase letter, number or '_'.\n"
-        "Error occurred near line 1, position 30: "
-        "{% block entry %}{% foreach BoLA %}");
+        "Error occurred near line 1, position 30:\n"
+        "{% block entry %}{% foreach BoLA %}\n"
+        "                             ^");
     blogc_error_free(err);
 }
 
@@ -710,8 +736,9 @@ test_template_parse_invalid_foreach_variable2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid foreach variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 29: {% block entry %}"
-        "{% foreach 0123 %}");
+        "Error occurred near line 1, position 29:\n"
+        "{% block entry %}{% foreach 0123 %}\n"
+        "                            ^");
     blogc_error_free(err);
 }
 
@@ -727,8 +754,9 @@ test_template_parse_invalid_if_operator(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid 'if' operator. Must be '<', '>', '<=', '>=', '==' or '!='.\n"
-        "Error occurred near line 1, position 29: "
-        "{% block entry %}{% if BOLA = \"asd\" %}");
+        "Error occurred near line 1, position 29:\n"
+        "{% block entry %}{% if BOLA = \"asd\" %}\n"
+        "                            ^");
     blogc_error_free(err);
 }
 
@@ -744,8 +772,9 @@ test_template_parse_invalid_if_operand(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid 'if' operand. Must be double-quoted static string or variable.\n"
-        "Error occurred near line 1, position 32: "
-        "{% block entry %}{% if BOLA == asd %}");
+        "Error occurred near line 1, position 32:\n"
+        "{% block entry %}{% if BOLA == asd %}\n"
+        "                               ^");
     blogc_error_free(err);
 }
 
@@ -761,8 +790,9 @@ test_template_parse_invalid_if_operand2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Found an open double-quoted string.\n"
-        "Error occurred near line 1, position 31: "
-        "{% block entry %}{% if BOLA == \"asd %}");
+        "Error occurred near line 1, position 32:\n"
+        "{% block entry %}{% if BOLA == \"asd %}\n"
+        "                               ^");
     blogc_error_free(err);
 }
 
@@ -778,8 +808,9 @@ test_template_parse_invalid_if_operand3(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid 'if' operand. Must be double-quoted static string or variable.\n"
-        "Error occurred near line 1, position 32: "
-        "{% block entry %}{% if BOLA == 0123 %}");
+        "Error occurred near line 1, position 32:\n"
+        "{% block entry %}{% if BOLA == 0123 %}\n"
+        "                               ^");
     blogc_error_free(err);
 }
 
@@ -795,7 +826,9 @@ test_template_parse_invalid_else1(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "'else' statement without an open 'if', 'ifdef' or 'ifndef' statement.\n"
-        "Error occurred near line 1, position 8: {% else %}");
+        "Error occurred near line 1, position 8:\n"
+        "{% else %}\n"
+        "       ^");
     blogc_error_free(err);
 }
 
@@ -811,8 +844,9 @@ test_template_parse_invalid_else2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "More than one 'else' statement for an open 'if', 'ifdef' or 'ifndef' "
-        "statement.\nError occurred near line 1, position 60: {% if BOLA == \"123\" "
-        "%}{% if GUDA == \"1\" %}{% else %}{% else %}");
+        "statement.\nError occurred near line 1, position 60:\n"
+        "{% if BOLA == \"123\" %}{% if GUDA == \"1\" %}{% else %}{% else %}\n"
+        "                                                           ^");
     blogc_error_free(err);
 }
 
@@ -835,7 +869,9 @@ test_template_parse_invalid_else3(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "More than one 'else' statement for an open 'if', 'ifdef' or 'ifndef' "
-        "statement.\nError occurred near line 7, position 8: {% else %}");
+        "statement.\nError occurred near line 7, position 8:\n"
+        "{% else %}\n"
+        "       ^");
     blogc_error_free(err);
 }
 
@@ -851,7 +887,9 @@ test_template_parse_invalid_block_end(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Must end with '%}'.\n"
-        "Error occurred near line 1, position 16: {% block entry }}");
+        "Error occurred near line 1, position 16:\n"
+        "{% block entry }}\n"
+        "               ^");
     blogc_error_free(err);
 }
 
@@ -867,8 +905,9 @@ test_template_parse_invalid_variable_name(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 21: "
-        "{% block entry %}{{ bola }}{% endblock %}");
+        "Error occurred near line 1, position 21:\n"
+        "{% block entry %}{{ bola }}{% endblock %}\n"
+        "                    ^");
     blogc_error_free(err);
 }
 
@@ -884,8 +923,9 @@ test_template_parse_invalid_variable_name2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must be uppercase letter, number or '_'.\n"
-        "Error occurred near line 1, position 22: "
-        "{% block entry %}{{ Bola }}{% endblock %}");
+        "Error occurred near line 1, position 22:\n"
+        "{% block entry %}{{ Bola }}{% endblock %}\n"
+        "                     ^");
     blogc_error_free(err);
 }
 
@@ -901,8 +941,9 @@ test_template_parse_invalid_variable_name3(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid variable name. Must begin with uppercase letter.\n"
-        "Error occurred near line 1, position 21: {% block entry %}{{ 0123 }}"
-        "{% endblock %}");
+        "Error occurred near line 1, position 21:\n"
+        "{% block entry %}{{ 0123 }}{% endblock %}\n"
+        "                    ^");
     blogc_error_free(err);
 }
 
@@ -918,8 +959,9 @@ test_template_parse_invalid_variable_end(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Must end with '}}'.\n"
-        "Error occurred near line 1, position 26: "
-        "{% block entry %}{{ BOLA %}{% endblock %}");
+        "Error occurred near line 1, position 26:\n"
+        "{% block entry %}{{ BOLA %}{% endblock %}\n"
+        "                         ^");
     blogc_error_free(err);
 }
 
@@ -935,7 +977,9 @@ test_template_parse_invalid_close(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Must end with '}'.\n"
-        "Error occurred near line 1, position 17: {% block entry %%");
+        "Error occurred near line 1, position 17:\n"
+        "{% block entry %%\n"
+        "                ^");
     blogc_error_free(err);
 }
 
@@ -951,8 +995,9 @@ test_template_parse_invalid_close2(void **state)
     assert_int_equal(err->type, BLOGC_ERROR_TEMPLATE_PARSER);
     assert_string_equal(err->msg,
         "Invalid statement syntax. Must end with '}'.\n"
-        "Error occurred near line 1, position 27: "
-        "{% block entry %}{{ BOLA }%{% endblock %}");
+        "Error occurred near line 1, position 27:\n"
+        "{% block entry %}{{ BOLA }%{% endblock %}\n"
+        "                          ^");
     blogc_error_free(err);
 }