#16 Pass command-line arguments to Lua programs

README.md

@@ -442,9 +442,9 @@ Which results in an indented bullet list:
 
 ## Lua Examples
 
-### JSON (again)
+### Accessing the Tree from Lua and output to JSON
 
-First, we are going tell frangipanni to output via a Lua program called 'json.lua', and we will format the json with the 'jp' program.
+First, we are going tell frangipanni to output via a Lua program called `json.lua`, and we will format the json with the 'jp' program.
 
 ```
 $ <test/fixtures/simplechars.txt frangipanni -lua json.lua | jp @
@@ -453,19 +453,17 @@ $ <test/fixtures/simplechars.txt frangipanni -lua json.lua | jp @
 The Lua script uses the `github.com/layeh/gopher-json` module which is imported in the Lua. The data
 is made available in the variable `frangipanni` which has a table for each node, with fields
 
-* depth - in the tree starting from 0
-* lineNumber - the token was first detected
-* numMatched - the number of times the token was seen
-* sep - separation characters preceding the token
-* text - the token itself
-* children - a table containing the child nodes 
+* `depth` - in the tree starting from 0
+* `lineNumber` - the token was first detected
+* `numMatched` - the number of times the token was seen
+* `sep` - separation characters preceding the token
+* `text` - the token itself
+* `children` - a table containing the child nodes 
 
 ```Lua
 local json = require("json")
-
 print(json.encode(frangipanni))
 ```
-
 The output shows that all the fields of the parsed nodes are passed to Lua in a Table.
 The root node is empty except for it's children. The Lua script is therafore able to use
 the fields intelligently.
@@ -498,6 +496,39 @@ the fields intelligently.
 }
 ```
 
+### Accessing frangipanni command-line arguments from Lua
+
+frangipanni hands the command arguments to the Lua interpreter in the variable `frangipanni_args`. This holds a table keyed on the argument switch and holding the current value in a string. Command-line arguments found after switches are collected in the `args` array in this table. This example Lua program, `args.lua`, prints the table in JSON format:
+```Lua
+local json = require("json")
+print(json.encode(frangipanni_args))
+```
+The output is:
+```JSON
+$ ./frangipanni -breaks / -counts -depth 3 -level 20 -lua args.lua arg1 arg2 </dev/null | jp '@'
+{
+  "args": [
+    "arg1",
+    "arg2"
+  ],
+  "breaks": "/",
+  "chars": "false",
+  "counts": "true",
+  "depth": "3",
+  "down": "false",
+  "format": "indent",
+  "indent": "4",
+  "level": "20",
+  "lua": "args.lua",
+  "no-fold": "false",
+  "separators": "false",
+  "skip": "0",
+  "sort": "input",
+  "spacer": " ",
+  "version": "false"
+}
+```
+
 ### Markdown
 
 This example shows recursive scanning of the tree, with output format controlled by
@@ -549,6 +580,16 @@ or with `NUMBERED_LIST=1 ./frangipanni -lua markdown.lua <test/fixtures/simplech
    1. 1
    1. 2
 ```
+Which renders like this:
+1. Z
+1. 1.2
+1. A
+1. C
+   1. 2
+   1. D
+1. x.a
+   1. 1
+   1. 2
 
 ### XML
 

args.lua

@@ -0,0 +1,5 @@
+--
+-- Output command-line in JSON format
+--
+local json = require("json")
+print(json.encode(frangipanni_args))

frangipanni.go

@@ -345,9 +345,26 @@ func makeLuaTableFromNode(L *lua.LState, n *node) *lua.LTable {
 	return tb
 }
 
+func makeLuaTableFromFlags(L *lua.LState) *lua.LTable {
+	tb := L.CreateTable(6, 6)
+	flag.VisitAll(func(f *flag.Flag) {
+		if f.Name == "order" { // Deprecated
+			return
+		}
+		tb.RawSet(lua.LString(f.Name), lua.LString(f.Value.String()))
+	})
+	args := L.CreateTable(len(flag.Args()), len(flag.Args()))
+	for i, a := range flag.Args() {
+		args.RawSetInt(i+1, lua.LString(a))
+	}
+	tb.RawSet(lua.LString("args"), args)
+	return tb
+}
+
 func luaRun(out io.Writer, root *node) {
 	L := lua.NewState()
 	luajson.Preload(L)
+	L.SetGlobal("frangipanni_args", makeLuaTableFromFlags(L))
 	L.SetGlobal("frangipanni", makeLuaTableFromNode(L, root))
 	defer L.Close()
 	if err := L.DoFile(luaFile); err != nil {

test/confidence.sh

@@ -12,6 +12,10 @@ then
   exit 1
 fi
 tempfile=$(mktemp)
+
+echo "--- -breaks / -counts -depth 3 -level 20 -lua args.lua ----------------------------------------------------------------------------------------------------" >> "$tempfile"
+../frangipanni -breaks / -counts -depth 3 -level 20 -lua ../args.lua arg1 arg2 </dev/null | jp '@' >> "$tempfile"
+
 for tf in fixtures/*
 do
     for sw in '' -chars '-breaks /' -separators -counts -no-fold '-level 2' '-depth 2' '-spacer ^ -indent 1 -counts'

test/fixtures.log

@@ -1,3 +1,25 @@
+--- -breaks / -counts -depth 3 -level 20 -lua args.lua ----------------------------------------------------------------------------------------------------
+{
+  "args": [
+    "arg1",
+    "arg2"
+  ],
+  "breaks": "/",
+  "chars": "false",
+  "counts": "true",
+  "depth": "3",
+  "down": "false",
+  "format": "indent",
+  "indent": "4",
+  "level": "20",
+  "lua": "../args.lua",
+  "no-fold": "false",
+  "separators": "false",
+  "skip": "0",
+  "sort": "input",
+  "spacer": " ",
+  "version": "false"
+}
 fixtures/find.txt---  ----------------------------------------------------------------------------------------------------
 proc/22468
     io