first commit

.gitattributes

@@ -0,0 +1 @@
+*.c linguist-language=Go

Makefile

@@ -0,0 +1,34 @@
+# Copyright 2019 <chaishushan{AT}gmail.com>. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+#
+# MnBook: Mini Markdown Book
+# https://github.com/wa-lang/mnbook
+#
+
+default:
+	mnbook serve
+
+build:
+	-rm book
+	mnbook build
+	-rm book/.gitignore
+	-rm -rf book/.git
+
+deploy:
+	-@make clean
+	mnbook build
+	-rm book/.gitignore
+	-rm -rf book/.git
+	-rm -rf book/examples
+
+	cd book && git init
+	cd book && git add .
+	cd book && git commit -m "first commit"
+	cd book && git branch -M gh-pages
+	cd book && git remote add origin [email protected]:chai2010/go-ast-book.git
+	cd book && git push -f origin gh-pages
+
+clean:
+	-rm -rf book

appendix/a-goyacc/calc.y

@@ -0,0 +1,63 @@
+/* Copyright 2019 <chaishushan{AT}gmail.com>. All rights reserved. */
+/* Use of this source code is governed by a Apache */
+/* license that can be found in the LICENSE file. */
+
+/* simplest version of calculator */
+
+%{
+package main
+
+import (
+	"fmt"
+)
+
+var idValueMap = map[string]int{}
+%}
+
+%union {
+	value int
+	id    string
+}
+
+%type  <value> exp factor term
+%token <value> NUMBER
+%token <id>    ID
+
+%token ADD SUB MUL DIV ABS
+%token LPAREN RPAREN ASSIGN
+%token EOL
+
+%%
+calclist
+	: // nothing
+	| calclist exp EOL {
+		idValueMap["_"] = $2
+		fmt.Printf("= %v\n", $2)
+	}
+	| calclist ID ASSIGN exp EOL {
+		idValueMap["_"] = $4
+		idValueMap[$2] = $4
+		fmt.Printf("= %v\n", $4)
+	}
+	;
+
+exp
+	: factor         { $$ = $1 }
+	| exp ADD factor { $$ = $1 + $3 }
+	| exp SUB factor { $$ = $1 - $3 }
+	;
+
+factor
+	: term            { $$ = $1 }
+	| factor MUL term { $$ = $1 * $3 }
+	| factor DIV term { $$ = $1 / $3 }
+	;
+
+term
+	: NUMBER            { $$ = $1 }
+	| ID                { $$ = idValueMap[$1] }
+	| ABS term          { if $2 >= 0 { $$ = $2 } else { $$ = -$2 } }
+	| LPAREN exp RPAREN { $$ = $2 }
+	;
+
+%%

appendix/a-goyacc/examples/calculator/Makefile

@@ -0,0 +1,18 @@
+# Copyright 2019 <chaishushan{AT}gmail.com>. All rights reserved.
+# Use of this source code is governed by a Apache
+# license that can be found in the LICENSE file.
+
+run:
+	make flex
+	make goyacc
+
+	@go fmt
+	go run .
+
+flex:
+	flex --prefix=yy --header-file=calc.lex.h -o calc.lex.c calc.l
+
+goyacc:
+	goyacc -o calc.y.go -p "calc" calc.y
+
+clean:

appendix/a-goyacc/examples/calculator/calc.l

@@ -0,0 +1,31 @@
+/* Copyright 2019 <chaishushan{AT}gmail.com>. All rights reserved. */
+/* Use of this source code is governed by a Apache */
+/* license that can be found in the LICENSE file. */
+
+%option noyywrap
+
+%{
+#include "tok.h"
+%}
+
+%%
+
+[_a-zA-Z]+ { return ID; }
+[0-9]+     { return NUMBER; }
+
+"+"    { return ADD; }
+"-"    { return SUB; }
+"*"    { return MUL; }
+"/"    { return DIV; }
+"|"    { return ABS; }
+
+"("    { return LPAREN; }
+")"    { return RPAREN; }
+"="    { return ASSIGN; }
+
+\n     { return EOL; }
+[ \t]  { /* ignore whitespace */ }
+.      { return ILLEGAL; }
+
+%%
+