Allow for preprocessor as a statement

Closes hadronized#64.
Closes hadronized#117.

Author: unjello

glsl/src/parsers.rs

@@ -1305,6 +1305,7 @@ pub fn multiplicative_expr(i: &str) -> ParserResult<syntax::Expr> {
 /// Parse a simple statement.
 pub fn simple_statement(i: &str) -> ParserResult<syntax::SimpleStatement> {
   alt((
+    map(preprocessor, syntax::SimpleStatement::Preprocessor),
     map(jump_statement, syntax::SimpleStatement::Jump),
     map(iteration_statement, syntax::SimpleStatement::Iteration),
     map(case_label, syntax::SimpleStatement::CaseLabel),

glsl/src/syntax.rs

@@ -1011,6 +1011,7 @@ impl Statement {
 /// Simple statement.
 #[derive(Clone, Debug, PartialEq)]
 pub enum SimpleStatement {
+  Preprocessor(Preprocessor),
   Declaration(Declaration),
   Expression(ExprStatement),
   Selection(SelectionStatement),

glsl/src/transpiler/glsl.rs

@@ -1343,6 +1343,7 @@ where
   F: Write,
 {
   match *sst {
+    syntax::SimpleStatement::Preprocessor(ref pp) => show_preprocessor(f, pp),
     syntax::SimpleStatement::Declaration(ref d) => show_declaration(f, d),
     syntax::SimpleStatement::Expression(ref e) => show_expression_statement(f, e),
     syntax::SimpleStatement::Selection(ref s) => show_selection_statement(f, s),

glsl/src/visitor.rs

@@ -1199,6 +1199,7 @@ macro_rules! make_host_trait {
 
         if visit == Visit::Children {
           match self {
+            syntax::SimpleStatement::Preprocessor(p) => p.$mthd_name(visitor),
             syntax::SimpleStatement::Declaration(d) => d.$mthd_name(visitor),
             syntax::SimpleStatement::Expression(e) => e.$mthd_name(visitor),
             syntax::SimpleStatement::Selection(s) => s.$mthd_name(visitor),