Fix a number of things.

README.md

@@ -1,14 +1,28 @@
 
 # Mk
 
-Mk is a reboot of the Plan 9 mk command, which itself is a replacement for make.
+Mk is a reboot of the Plan 9 mk command, which itself is [a successor to
-This tool is for anyone who loves make, but hates all its stupid bullshit.
+make]($). This tool is for anyone who loves make, but hates all its stupid
+bullshit.
+
+# Installation
+
+ 1. Install Go.
+ 2. Run `go install github.com/dcjones/mk`
 
 # Why Plan 9 mk is better than make
 
-Plan 9 mk blows make out of the water. Yet tragically, few use or have even heard
+Way back in the 90s, some smart guys at Bell Labs got together and decided to
-of it. Put simply, mk takes make, keeps its simple direct syntax, but fixes
+write new operating system to replace Unix. The idea was to keep everything that
-basically everything that's annoyed you over the years. To name a few things:
+was great about Unix, but totally disregard backwards compatibility in a quest
+for something better. The operating system they designed, Plan 9, had a lot of
+terrific ideas, and though some were cherry picked, the OS as a whole never
+really caught on.
+
+Among the gems in Plan 9 was a rewrite of the venerable Unix make
+command, in the form of mk. Simply put, mk is make, but with a large collection
+of relatively minor improvements, adding up to something more consistent,
+elegant, and powerful. To name a few specifics:
 
   1. Recipes are delimited by any indentation, not tab characters in particular.
   1. Phony targets are handled separately from file targets. Your mkfile won't
@@ -29,29 +43,30 @@ basically everything that's annoyed you over the years. To name a few things:
   1. Variables are expanded in recipes only if they are defined. They way you
      usually don't have to escape `$`.
 
-And much more! For more, read the original mk paper: ["Mk: a successor to
+And much more!
-make"](#).
 
 # Improvements over Plan 9 mk
 
 This mk stays mostly faithful to Plan 9, but makes a few (in my opinion)
 improvements.
 
-  1. A clean, modern implementation in go, that doesn't depend on the whole plan
+  1. A clean, modern implementation in Go, that doesn't depend on the whole Plan
-     9 for userspace stack.
+     9 stack.
-  1. Use go regular expressions, which are perl-like. The original mk used plan9
+  1. Use Go regular expressions, which are perl-like. The original mk used plan9
      regex, which few people know or care to learn.
   1. Allow blank lines in recipes. A recipe is any indented block of text, and
-     continues until a non-indented character or the end of the file.
+     continues until a non-indented character or the end of the file. (Similar
+     to blocks in Python.)
   1. Add an 'S' attribute to execute recipes with programs other than sh. This
      way, you don't have to separate your six line python script into its own
-     file. Just stick it in the mkfile.
+     file. Just stick it directly in the mkfile.
   1. Use sh syntax for command insertion (i.e. backticks) rather than rc shell
      syntax.
-
+  1. Pretty colors.
 
 # Current State
 
-Totally non-functional. Check back later!
+Functional, but with some bugs and some unimplemented minor features. Give it a
+try and see what you think!
 
 

expand.go

@@ -154,7 +154,9 @@ func expandSigil(input string, vars map[string][]string) ([]string, int) {
 		varvals, ok := vars[varname]
 		if ok {
 			return varvals, offset
-		}
+		} else {
+            return []string{"$" + input[:offset]}, offset
+        }
 	}
 
 	return []string{"$" + input}, len(input)

graph.go

@@ -56,10 +56,10 @@ type node struct {
 	flags     nodeFlag          // bitwise combination of node flags
 }
 
-// Create a new node
+
-func (g *graph) newnode(name string) *node {
+// Update a node's timestamp and 'exists' flag.
-	u := &node{name: name}
+func (u *node) updateTimestamp() {
-	info, err := os.Stat(name)
+	info, err := os.Stat(u.name)
 	if err == nil {
 		u.t = info.ModTime()
 		u.exists = true
@@ -67,11 +67,18 @@ func (g *graph) newnode(name string) *node {
 	} else {
 		_, ok := err.(*os.PathError)
 		if ok {
+            u.t =   time.Unix(0, 0)
 			u.exists = false
 		} else {
 			mkError(err.Error())
 		}
 	}
+}
+
+// Create a new node
+func (g *graph) newnode(name string) *node {
+	u := &node{name: name}
+    u.updateTimestamp()
 	g.nodes[name] = u
 	return u
 }
@@ -103,14 +110,10 @@ func buildgraph(rs *ruleSet, target string) *graph {
 	// keep track of how many times each rule is visited, to avoid cycles.
 	rulecnt := make([]int, len(rs.rules))
 	g.root = applyrules(rs, g, target, rulecnt)
-    println("cyclecheck")
     g.cyclecheck(g.root)
 	g.root.flags |= nodeFlagProbable
-    println("vacuous")
     g.vacuous(g.root)
-    println("ambiguous")
     g.ambiguous(g.root)
-    println("done")
 
 	return g
 }
@@ -192,7 +195,6 @@ func applyrules(rs *ruleSet, g *graph, target string, rulecnt []int) *node {
 			}
 
 			rulecnt[k] += 1
-            fmt.Println(rulecnt)
 			if len(r.prereqs) == 0 {
 				e := u.newedge(nil, r)
 				e.stem = stem

lex.go

@@ -1,17 +1,24 @@
-// TODO: Backquoted strings.
-// TODO: Comments
 
 package main
 
 import (
 	"strings"
 	"unicode/utf8"
+    "fmt"
 )
 
 type tokenType int
 
 const eof rune = '\000'
 
+// Rune's that cannot be part of a bare (unquoted) string.
+const nonBareRunes = " \t\n\r\\=:#'\""
+
+// Return true if the string contains whitespace only.
+func onlyWhitespace(s string) bool {
+    return strings.IndexAny(s, " \t\r\n") < 0
+}
+
 const (
 	tokenError tokenType = iota
 	tokenNewline
@@ -79,7 +86,9 @@ type lexer struct {
 type lexerStateFun func(*lexer) lexerStateFun
 
 func (l *lexer) lexerror(what string) {
-	l.errmsg = what
+    if l.errmsg == "" {
+        l.errmsg = what
+    }
 	l.emit(tokenError)
 }
 
@@ -173,6 +182,10 @@ func (l *lexer) acceptUntil(invalid string) {
 	for l.pos < len(l.input) && strings.IndexRune(invalid, l.peek()) < 0 {
 		l.next()
 	}
+
+    if l.peek() == eof {
+        l.lexerror(fmt.Sprintf("end of file encountered while looking for one of: %s", invalid))
+    }
 }
 
 // Skip characters from the valid string until the next is not.
@@ -189,6 +202,10 @@ func (l *lexer) skipUntil(invalid string) {
 	for l.pos < len(l.input) && strings.IndexRune(invalid, l.peek()) < 0 {
 		l.skip()
 	}
+
+    if l.peek() == eof {
+        l.lexerror(fmt.Sprintf("end of file encountered while looking for one of: %s", invalid))
+    }
 }
 
 // Start a new lexer to lex the given input.
@@ -252,8 +269,10 @@ func lexTopLevel(l *lexer) lexerStateFun {
 		return lexBackQuotedWord
 	}
 
-	// TODO: No! The lexer can get stuck in a loop this way.
+    if strings.IndexRune(nonBareRunes, c) >= 0 {
-	// Check if the next charar is a valid bare string chacter. If not, error.
+        l.lexerror(fmt.Sprintf("expected a unquoted string, but found '%c'", c))
+    }
+
 	return lexBareWord
 }
 
@@ -287,12 +306,17 @@ func lexInclude(l *lexer) lexerStateFun {
 
 func lexDoubleQuotedWord(l *lexer) lexerStateFun {
 	l.next() // '"'
-	for l.peek() != '"' {
+	for l.peek() != '"' && l.peek() != eof {
 		l.acceptUntil("\\\"")
 		if l.accept("\\") {
 			l.accept("\"")
 		}
 	}
+
+    if l.peek() == eof {
+        l.lexerror("end of file encountered while parsing a quoted string.")
+    }
+
 	l.next() // '"'
 	return lexBareWord
 }
@@ -320,13 +344,14 @@ func lexRecipe(l *lexer) lexerStateFun {
 		}
 	}
 
-	// TODO: don't emit if there is only whitespace in the recipe
+    if !onlyWhitespace(l.input[l.start:l.pos]) {
-	l.emit(tokenRecipe)
+        l.emit(tokenRecipe)
+    }
 	return lexTopLevel
 }
 
 func lexBareWord(l *lexer) lexerStateFun {
-	l.acceptUntil(" \t\n\r\\=:#'\"")
+	l.acceptUntil(nonBareRunes)
 	if l.peek() == '"' {
 		return lexDoubleQuotedWord
 	} else if l.peek() == '\'' {

mk.go

@@ -128,6 +128,7 @@ func mkNode(g *graph, u *node) {
 	for i := range prereqs {
 		prereqs[i].mutex.Lock()
 		// needs to be built?
+        u.updateTimestamp()
 		if !prereqs[i].exists || e.r.attributes.virtual || rebuildall || (u.exists && u.t.Before(prereqs[i].t)) {
 			switch prereqs[i].status {
 			case nodeStatusReady:
@@ -143,12 +144,7 @@ func mkNode(g *graph, u *node) {
 	e.r.mutex.Unlock()
 
 	// wait until all the prereqs are built
-	//fmt.Printf("%s: %d\n", u.name, pending)
 	for pending > 0 {
-		//for i := range prereqs {
-		//fmt.Println(prereqs[i].name)
-		//}
-
 		s := <-prereqstat
 		pending--
 		if s == nodeStatusFailed {
@@ -164,8 +160,6 @@ func mkNode(g *graph, u *node) {
 		}
 		finishSubproc()
 	}
-
-	//mkPrintSuccess("finished mking " + u.name)
 }
 
 func mkError(msg string) {
@@ -177,7 +171,7 @@ func mkPrintError(msg string) {
 	if !nocolor {
 		os.Stderr.WriteString(ansiTermRed)
 	}
-	fmt.Fprintf(os.Stderr, "mk: %s\n", msg)
+	fmt.Fprintf(os.Stderr, "%s", msg)
 	if !nocolor {
 		os.Stderr.WriteString(ansiTermDefault)
 	}

parse.go

@@ -5,9 +5,10 @@ package main
 
 import (
 	"fmt"
-	"os"
 	"regexp"
 	"strings"
+    "io/ioutil"
+    "os"
 )
 
 type parser struct {
@@ -19,10 +20,10 @@ type parser struct {
 
 // Pretty errors.
 func (p *parser) parseError(context string, expected string, found token) {
-	fmt.Fprintf(os.Stderr, "%s:%d: syntax error: ", p.name, found.line)
+    mkPrintError(fmt.Sprintf("%s:%d: syntax error: ", p.name, found.line))
-	fmt.Fprintf(os.Stderr, "while %s, expected %s but found \"%s\".\n",
+	mkPrintError(fmt.Sprintf("while %s, expected %s but found '%s'.\n",
-		context, expected, found.String())
+		context, expected, found.String()))
-	os.Exit(1)
+    mkError("")
 }
 
 // More basic errors.
@@ -31,9 +32,7 @@ func (p *parser) basicErrorAtToken(what string, found token) {
 }
 
 func (p *parser) basicErrorAtLine(what string, line int) {
-	fmt.Fprintf(os.Stderr, "%s:%d: syntax error: %s\n",
+	mkError(fmt.Sprintf("%s:%d: syntax error: %s\n", p.name, line, what))
-		p.name, line, what)
-	os.Exit(1)
 }
 
 // Accept a token for use in the current statement being parsed.
@@ -66,8 +65,7 @@ func parseInto(input string, name string, rules *ruleSet) {
 	state := parseTopLevel
 	for t := range tokens {
 		if t.typ == tokenError {
-			// TODO: fancier error messages
+            p.basicErrorAtLine(l.errmsg, t.line)
-			fmt.Fprintf(os.Stderr, "Error: %s", l.errmsg)
 			break
 		}
 
@@ -137,7 +135,7 @@ func parsePipeInclude(p *parser, t token) parserStateFun {
 		p.tokenbuf = append(p.tokenbuf, t)
 
 	default:
-		// TODO: Complain about unexpected tokens.
+        p.parseError("parsing piped include", "a shell command", t)
 	}
 
 	return parsePipeInclude
@@ -147,15 +145,25 @@ func parsePipeInclude(p *parser, t token) parserStateFun {
 func parseRedirInclude(p *parser, t token) parserStateFun {
 	switch t.typ {
 	case tokenNewline:
-		// TODO:
+        filename := ""
-		// Open the file, read its context, call parseInto recursively.
+        for i := range p.tokenbuf {
-		// Clear out p.tokenbuf
+            filename += p.tokenbuf[i].val
+        }
+        file, err := os.Open(filename)
+        if err != nil {
+            p.basicErrorAtToken(fmt.Sprintf("cannot open %s", filename), p.tokenbuf[0])
+        }
+        input, _ := ioutil.ReadAll(file)
+        parseInto(string(input), filename, p.rules)
+
+        p.clear()
+        return parseTopLevel
 
 	case tokenWord:
-		// TODO:
+		p.tokenbuf = append(p.tokenbuf, t)
 
 	default:
-		// TODO: Complain about unexpected tokens.
+        p.parseError("parsing include", "a file name", t)
 	}
 
 	return parseRedirInclude
@@ -182,7 +190,7 @@ func parseEqualsOrTarget(p *parser, t token) parserStateFun {
 		return parseAttributesOrPrereqs
 
 	default:
-		p.parseError("reading a a target or assignment",
+		p.parseError("reading a target or assignment",
 			"'=', ':', or another target", t)
 	}
 

recipe.go

@@ -86,7 +86,7 @@ func dorecipe(target string, u *node, e *edge) bool {
 			prereqs = append(prereqs, u.prereqs[i].v.name)
 		}
 	}
-	vars["prereqs"] = prereqs
+	vars["prereq"] = prereqs
 
 	input := expandRecipeSigils(e.r.recipe, vars)
 	sh := "sh"
@@ -113,8 +113,6 @@ func dorecipe(target string, u *node, e *edge) bool {
 		true,
 		false)
 
-	// TODO: update the timestamps of each target
-
 	return success
 }