commit d8df1c019a874612f0df6d2231581e395714175a
Author: cosmonaut <evan@moonside.games>
Date:   Fri Apr 16 00:35:35 2021 -0700

    initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e69de29
diff --git a/ast.h b/ast.h
new file mode 100644
index 0000000..24e4213
--- /dev/null
+++ b/ast.h
@@ -0,0 +1,168 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+typedef enum
+{
+    Assignment,
+    BinaryExpression,
+    Boolean,
+    Comment,
+    Expression,
+    ForLoop,
+    Identifier,
+    Number,
+    Return,
+    String,
+    UnaryExpression
+} SyntaxKind;
+
+typedef enum
+{
+    Negate
+} UnaryOperator;
+
+typedef enum
+{
+    Add,
+    Subtract
+} BinaryOperator;
+
+typedef union
+{
+    UnaryOperator unaryOperator;
+    BinaryOperator binaryOperator;
+} Operator;
+
+typedef union
+{
+    const char *string;
+    uint64_t number;
+} Value;
+
+typedef struct Node
+{
+    SyntaxKind syntaxKind;
+    struct Node **children;
+    uint32_t childCount;
+    union
+    {
+        UnaryOperator unaryOperator;
+        BinaryOperator binaryOperator;
+    } operator;
+    Value value;
+} Node;
+
+const char* SyntaxKindString(SyntaxKind syntaxKind)
+{
+    switch(syntaxKind)
+    {
+        case Assignment: return "Assignment";
+        case BinaryExpression: return "BinaryExpression";
+        case Identifier: return "Identifier";
+        case Number: return "Number";
+        case String: return "String";
+        case UnaryExpression: return "UnaryExpression";
+        default: return "Unknown";
+    }
+}
+
+Node* MakeIdentifierNode(
+    const char *id
+) {
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = Identifier;
+    node->value.string = id;
+    node->childCount = 0;
+    return node;
+}
+
+Node* MakeNumberNode(
+    const char *numberString
+) {
+    char *ptr;
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = Number;
+    node->value.number = strtoul(numberString, &ptr, 10);
+    node->childCount = 0;
+    return node;
+}
+
+Node* MakeStringNode(
+    const char *string
+) {
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = String;
+    node->value.string = string;
+    node->childCount = 0;
+    return node;
+}
+
+Node* MakeUnaryNode(
+    UnaryOperator operator,
+    Node *child
+) {
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = UnaryExpression;
+    node->operator.unaryOperator = operator;
+    node->children = malloc(sizeof(Node*));
+    node->children[0] = child;
+    node->childCount = 1;
+    return node;
+}
+
+Node* MakeBinaryNode(
+    BinaryOperator operator,
+    Node *left,
+    Node *right
+) {
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = BinaryExpression;
+    node->operator.binaryOperator = operator;
+    node->children = malloc(sizeof(Node*) * 2);
+    node->children[0] = left;
+    node->children[1] = right;
+    node->childCount = 2;
+    return node;
+}
+
+static void PrintBinaryOperator(BinaryOperator expression)
+{
+    switch (expression)
+    {
+        case Add:
+            printf("+");
+            break;
+
+        case Subtract:
+            printf("-");
+            break;
+    }
+
+    printf("\n");
+}
+
+static void PrintNode(Node *node)
+{
+    printf("%s\n", SyntaxKindString(node->syntaxKind));
+    switch (node->syntaxKind)
+    {
+        case BinaryExpression:
+            PrintBinaryOperator(node->operator.binaryOperator);
+            break;
+
+        case Number:
+            printf("%lu\n", node->value.number);
+            break;
+    }
+}
+
+void PrintTree(Node *node)
+{
+    uint32_t i;
+    PrintNode(node);
+    for (i = 0; i < node->childCount; i += 1)
+    {
+        PrintTree(node->children[i]);
+    }
+}
diff --git a/wraith.lex b/wraith.lex
new file mode 100644
index 0000000..c08cdf9
--- /dev/null
+++ b/wraith.lex
@@ -0,0 +1,35 @@
+%{
+extern int yywrap() { return 1; }
+%}
+
+%%
+[0-9]+                      return NUMBER;
+[a-zA-Z][a-zA-Z0-9]*        return ID;
+\"[a-zA-Z][a-zA-Z0-9]*\"    return STRING;
+"+"                         return PLUS;
+"-"                         return MINUS;
+"*"                         return MULTIPLY;
+"/"                         return DIVIDE;
+"%"                         return MOD;
+"<"                         return LESS_THAN;
+">"                         return GREATER_THAN;
+"="                         return EQUAL;
+"\""                        return QUOTE;
+"!"                         return BANG;
+"|"                         return BAR;
+"&"                         return AMPERSAND;
+"."                         return POINT;
+","                         return COMMA;
+";"                         return SEMICOLON;
+":"                         return COLON;
+"?"                         return QUESTION;
+"("                         return LEFT_PAREN;
+")"                         return RIGHT_PAREN;
+"["                         return LEFT_BRACKET;
+"]"                         return RIGHT_BRACKET;
+"{"                         return LEFT_BRACE;
+"}"                         return RIGHT_BRACE;
+"//"                        return COMMENT;
+"\n"                        return NEWLINE;
+[ \t]                       ;
+%%
diff --git a/wraith.y b/wraith.y
new file mode 100644
index 0000000..3a3bd90
--- /dev/null
+++ b/wraith.y
@@ -0,0 +1,91 @@
+%token NUMBER
+%token ID
+%token STRING
+%token PLUS
+%token MINUS
+%token MULTIPLY
+%token DIVIDE
+%token MOD
+%token EQUAL
+%token LESS_THAN
+%token GREATER_THAN
+%token QUOTE
+%token BANG
+%token BAR
+%token AMPERSAND
+%token POINT
+%token COMMA
+%token SEMICOLON
+%token COLON
+%token QUESTION
+%token LEFT_PAREN
+%token RIGHT_PAREN
+%token LEFT_BRACE
+%token RIGHT_BRACE
+%token LEFT_BRACKET
+%token RIGHT_BRACKET
+%token COMMENT
+%token NEWLINE
+
+%left PLUS MINUS
+%left BANG
+%left LEFT_PAREN RIGHT_PAREN
+
+%{
+#include "ast.h"
+#define YYSTYPE struct Node*
+%}
+
+%%
+Main                    : Expression NEWLINE
+                        {
+                            PrintTree($1);
+                        }
+
+PrimaryExpression       : ID
+                        {
+                            $$ = MakeIdentifierNode(yytext);
+                        }
+                        | NUMBER
+                        {
+                            $$ = MakeNumberNode(yytext);
+                        }
+                        | STRING
+                        {
+                            $$ = MakeStringNode(yytext);
+                        }
+                        | LEFT_PAREN Expression RIGHT_PAREN
+                        ;
+
+UnaryExpression         : BANG Expression
+                        {
+                            $$ = MakeUnaryNode(Negate, $2);
+                        }
+
+BinaryExpression        : Expression PLUS Expression
+                        {
+                            $$ = MakeBinaryNode(Add, $1, $3);
+                        }
+                        | Expression MINUS Expression
+                        {
+                            $$ = MakeBinaryNode(Subtract, $1, $3);
+                        }
+
+Expression              : PrimaryExpression
+                        | UnaryExpression
+                        | BinaryExpression
+                        ;
+%%
+
+#include "lex.yy.c"
+
+/* yacc error handler */
+void yyerror(char *s)
+{
+    fprintf (stderr, "%s\n", s);
+}
+
+int main(void)
+{
+    return yyparse();
+}