From d25c1a379a67e489ecfbf181b361f13feb2ca12d Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Fri, 16 Mar 2018 22:11:05 -0700
Subject: [PATCH] Add function to search for reserved operators.

---
 CMakeLists.txt     |  2 +-
 include/reserved.h | 41 +++++++++++++++++++++++++++++++++++++++++
 src/reserved.c     | 21 +++++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 include/reserved.h
 create mode 100644 src/reserved.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6377365..2bdf8ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,7 @@ project(libabacus)
 
 add_compile_options(-pedantic -Wall)
 
-add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c)
+add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c)
 add_executable(libabacus src/main.c)
 add_subdirectory(external/liblex)
 
diff --git a/include/reserved.h b/include/reserved.h
new file mode 100644
index 0000000..f4f93e7
--- /dev/null
+++ b/include/reserved.h
@@ -0,0 +1,41 @@
+#ifndef LIBABACUS_RESERVED_H
+#define LIBABACUS_RESERVED_H
+
+#include "result.h"
+#include "parsetype.h"
+#include "tree.h"
+#include "value.h"
+#include "libabacus.h"
+
+/**
+ * Struct that represents a reserved operator that contains
+ * interpreter-internal behavior.
+ */
+struct libab_reserved_operator_s {
+    /**
+     * The reserved operator.
+     */
+    const char* op;
+    /**
+     * The precedence of this operator.
+     */
+    int precedence;
+    /**
+     * The associativity of this operator.
+     */
+    int associativity;
+};
+
+typedef struct libab_reserved_operator_s libab_reserved_operator;
+
+/**
+ * Attempts to find a reserved operator with the given name.
+ * This function operates under the assumption that there are
+ * few reserved operators in libabacus. As such, it does effectively
+ * a polynomial time search - strcmp for every element until the operator is found.
+ * @param name the name to search for.
+ * @return the reserved operator, if it is found.
+ */
+const libab_reserved_operator* libab_find_reserved_operator(const char* name);
+
+#endif
diff --git a/src/reserved.c b/src/reserved.c
new file mode 100644
index 0000000..c14f9ba
--- /dev/null
+++ b/src/reserved.c
@@ -0,0 +1,21 @@
+#include "reserved.h"
+#include "string.h"
+
+static const libab_reserved_operator libab_reserved_operators[] = {
+    {
+        "=", /* Assignment */
+        0, /* Lowest precedence */
+        1 /* Right associative, a = b = 6 should be a = (b = 6) */
+    }
+};
+
+const libab_reserved_operator* libab_find_reserved_operator(const char* name) {
+    static const size_t element_count = 
+        sizeof(libab_reserved_operators) / sizeof(libab_reserved_operator);
+    size_t i;
+    for(i = 0; i < element_count; i++) {
+        if(strcmp(name, libab_reserved_operators[i].op) == 0)
+            return &libab_reserved_operators[i];
+    }
+    return NULL;
+}