Implement basic stdout emitter

htmlcc/__main__.py

@@ -16,13 +16,14 @@
 
 from .emitter import Emitter, known_emitters
 from .emitter.cgit import CgitEmitter
+from .emitter.stdout import StdoutEmitter
 from .parser import Parser
 
 import argparse
 
 # Initialise ArgumentParser
 arg_parser = argparse.ArgumentParser(prog='htmlcc', description='Statically compiled HTML templates for C')
-arg_parser.add_argument('--emitter', default='cgit', choices=list(known_emitters.keys()))
+arg_parser.add_argument('--emitter', default='stdout', choices=list(known_emitters.keys()))
 arg_parser.add_argument('filename', nargs='+')
 
 args = arg_parser.parse_args()

htmlcc/emitter/stdout.py

@@ -0,0 +1,86 @@
+#   htmlcc - Statically compiled HTML templates for C
+#   Copyright (C) 2025  Lee Yingtong Li
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from . import Emitter, register_emitter
+
+class StdoutEmitter(Emitter):
+	"""Emitter which prints templates to stdout (useful for testing/demonstration)"""
+	
+	def emit_preamble(self) -> None:
+		self.emit(r'''#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void output_variable_encoded(char *variable, bool encode_quotes) {
+	// First compute size of buffer required
+	size_t extra_chars = 0;
+	char *ptr = variable;
+	for (; *ptr != '\0'; ptr++) {
+		if (*ptr == '&') { extra_chars += 4; }
+		if (*ptr == '<') { extra_chars += 3; }
+		if (*ptr == '"' && encode_quotes) { extra_chars += 5; }
+		if (*ptr == '\'' && encode_quotes) { extra_chars += 4; }
+	}
+	
+	size_t len = ptr - variable;
+	char *buf = malloc(len + extra_chars + 1);
+	
+	// Replace characters
+	char *c_inp = variable;
+	char *c_out = buf;
+	for (; *c_inp != '\0'; c_inp++) {
+		if (*c_inp == '&') {
+			*c_out++ = '&'; *c_out++ = 'a'; *c_out++ = 'm'; *c_out++ = 'p'; *c_out++ = ';';
+		} else if (*c_inp == '<') {
+			*c_out++ = '&'; *c_out++ = 'l'; *c_out++ = 't'; *c_out++ = ';';
+		} else if (*c_inp == '"' && encode_quotes) {
+			*c_out++ = '&'; *c_out++ = 'q'; *c_out++ = 'u'; *c_out++ = 'o'; *c_out++ = 't'; *c_out++ = ';';
+		} else if (*c_inp == '\'' && encode_quotes) {
+			*c_out++ = '&'; *c_out++ = '#'; *c_out++ = '3'; *c_out++ = '9'; *c_out++ = ';';
+		} else {
+			*c_out++ = *c_inp;
+		}
+	}
+	*c_out = '\0';
+	
+	printf("%s", buf);
+	free(buf);
+}
+
+void output_variable_as_attr(char *variable) {
+	output_variable_encoded(variable, true);
+}
+
+void output_variable_as_text(char *variable) {
+	output_variable_encoded(variable, false);
+}''')
+	
+	def output_literal_string(self, literal_string: str) -> None:
+		self.emit(f'printf("%s", {self.escape_cstr(literal_string)});')
+	
+	def output_variable_as_attr(self, variable: str) -> None:
+		self.emit(f'output_variable_as_attr({variable});')
+	
+	def output_variable_as_text(self, variable: str) -> None:
+		self.emit(f'output_variable_as_text({variable});')
+	
+	def output_variable_formatted(self, format_string: str, variable: str) -> None:
+		self.emit(f'printf({self.escape_cstr(format_string)}, {variable});')
+	
+	def output_variable_urlencoded(self, variable: str) -> None:
+		raise NotImplementedError('urlencode filter is not implemented for the stdout emitter')
+
+register_emitter('stdout', StdoutEmitter)