Switched from .org to git of .el & readme

4 files changed, 403 insertions, 671 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f6acbf1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+ob-spice.org
diff --git a/ob-spice.el b/ob-spice.el
new file mode 100644
index 0000000..f3dc9c0
--- /dev/null
+++ b/ob-spice.el
@@ -0,0 +1,283 @@
+;;; ob-spice.el --- Babel Functions for spice
+;;; -*- coding: utf-8 -*-
+
+;; License: GPL v3, or any later version
+;;
+;; This file is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+;;
+;; This file is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Org-Babel support for evaluating spice.
+
+;;; Requirements:
+
+;; - ngspice :: http://ngspice.sourceforge.net/
+
+;;; Code:
+
+(require 'ob)
+
+(make-comint "spice" "ngspice")
+
+(defvar org-babel-spice-eoe-indicator ":org_babel_spice_eoe"
+  "String to indicate that evaluation has completed.")
+
+(defvar org-babel-spice-command "ngspice"
+  "Name of command to use for executing ngspice.")
+(defun org-babel-spice-initiate-session (&optional session dir _params)
+  "Initiate a ngspice session.
+Create comint buffer SESSION running ngspice starting in
+default-directory or DIR if specified."
+  (let* ((sessionname (if (or (not session) (string= session "none"))
+                          "spice" session))
+         (session (make-comint sessionname org-babel-spice-command)))
+    (if (and dir (file-name-absolute-p dir))
+	;; absolute dir
+	(comint-simple-send session (format "cd %s" dir))
+      ;; relative dir
+      (comint-simple-send session (format "cd %s" default-directory))
+    session
+    )))
+(defun org-babel-prep-session:spice (session params)
+  "Prepare SESSION according to header arguments in PARAMS."
+  (let ((session (org-babel-spice-initiate-session session))
+        (var-lines (org-babel-variable-assignments:spice params)))
+    (org-babel-comint-in-buffer session
+      (sit-for .5) (goto-char (point-max))
+      (mapc (lambda (var)
+              (insert var) (comint-send-input nil t)
+              (org-babel-comint-wait-for-output session)
+              (sit-for .1) (goto-char (point-max))) var-lines))
+    session))
+(defun org-babel-load-session:spice (session body params)
+  "Load BODY into SESSION."
+  (save-window-excursion
+    (let ((buffer (org-babel-prep-session:spice session params)))
+      (with-current-buffer buffer
+        (goto-char (process-mark (get-buffer-process (current-buffer))))
+        (insert (org-babel-chomp body)))
+      buffer)))
+
+;; helper
+
+(defun org-babel-variable-assignments:spice (params)
+  "Return a list of spice statements to set the variables in PARAMS."
+  (mapcar
+   (lambda (pair)
+     (format "set %s=%s"
+             (car pair)
+             (org-babel-spice-var-to-spice (cdr pair))))
+   (org-babel--get-vars params)))
+(defun org-babel-spice-var-to-spice (var)
+  "Convert VAR into a spice variable."
+  (if (listp var)
+      (concat "( " (mapconcat #'org-babel-spice-var-to-spice var " ") " )")
+    (format "%S" var)))
+
+;; (lambda (text) (setq body (concat text "\n" body)))
+(defun org-babel-spice-vector-search (body vars)
+  "Replace first instance in BODY for all VARS."
+  (mapc (lambda (pair)
+          (if (string-match (format
+                             "\\$%s\\[\\([0-9]\\)\\]"
+                             (car pair))
+                            body)
+              (let ((replacement (nth
+                                  (string-to-number (match-string 1 body))
+                                  pair)))
+                (setq body(format "%s%s%s"
+                                  (substring body 0 (match-beginning
+                                                     0))
+                                  replacement
+                                  (substring body (match-end 0)))))))
+        vars)
+  body
+  )
+
+(defun org-babel-spice-replace-vars (body vars)
+  "Expand BODY according to VARS."
+  (let ((old-body ""))
+    ;; replace vector variables preceded by '$' and followed by the
+    ;; index in square brackets starting at 0. Matches without
+    ;; preceding or succeeding spaces.
+    (while (not (string= old-body body))
+      (setq old-body body)
+      (setq body (org-babel-spice-vector-search body vars))
+      )
+    ;; replace any variable names preceded by '$' with the actual
+    ;; value of the variable. Matches only with succeeding space or
+    ;; end of line to prevent namespace limitations.
+    (mapc (lambda (pair)
+            (setq body (replace-regexp-in-string
+                        (format "\\$%s\\( \\)\\|\\$%s$" (car pair)
+                                (car pair))
+                        (format "%s\1" (cdr pair))
+                        body)))
+          vars)
+    body))
+(defun org-babel-expand-body:spice (body params)
+  "Expand BODY according to PARAMS, return the expanded body."
+  (let ((vars (org-babel--get-vars params))
+        (prologue (cdr (assq :prologue params)))
+        (epilogue (cdr (assq :epilogue params)))
+        (file (cdr (assq :file params))))
+    (setq body (org-babel-spice-replace-vars body vars))
+    ;; TODO :file stuff ....
+
+    ;; add prologue/epilogue
+    (when prologue (setq body (concat prologue "\n" body)))
+    (when epilogue (setq body (concat body "\n" epilogue)))
+    body))
+
+(defun org-babel-spice-trim-body (body)
+  "Prepare BODY to be used in interactive ngspice session."
+  ;; random control codes after $var inserts
+  (replace-regexp-in-string
+   "
" " "
+   ;; .control .endc lines
+   (replace-regexp-in-string
+    "^ *\\.\\(control\\|endc\\) *$" ""
+    ;; comment lines
+    (replace-regexp-in-string
+     "^ *\\*.*$" "" body))))
+(defun org-babel-execute:spice (body params)
+  "Execute a block of Spice code with Babel.
+This function is called by `org-babel-execute-src-block'."
+  (let* (;(body (org-babel-expand-body:spice body params))
+         (gnuplot (cdr (assq :gnuplot params)))
+         (result-params (cdr (assq :result-params params)))
+         (result-type (cdr (assq :result-type params)))
+         (session (org-babel-spice-initiate-session
+                   (cdr (assq :session params))
+                   (cdr (assq :dir params))))
+         (vars (org-babel--get-vars params))
+         (no-source (cdr (assq :no-source params)))
+         (break-index (if (string-match "^ *\.end *$" body)
+                          (match-end 0) 0))
+         ;;vars need to be replaced as they don't work when using source
+         (circuit-body (org-babel-expand-body:spice
+                        (substring body 0 break-index)
+                        (assq-delete-all :epilogue (copy-alist params))))
+         ;; todo: replace vars. :-( → set vars break when doing something like $file.txt
+         (control-body (org-babel-spice-trim-body (substring body break-index)))
+         (full-control-body (if (not (string= control-body ""))
+				(org-babel-expand-body:generic
+				 control-body
+				 (assq-delete-all :prologue (copy-alist params))
+				 (org-babel-variable-assignments:spice params)) ""))
+         (circuit-file (if circuit-body (org-babel-temp-file "spice-body-" ".cir")))
+         (result))
+
+
+    (message (concat "circuit:\n" circuit-body))
+    (message (concat "\n-----\ncontrol:\n" control-body))
+
+    ;; Source circuit-body
+    (with-temp-file circuit-file (insert circuit-body))
+    ;; Evaluate
+    (setq result (org-babel-spice-evaluate session full-control-body
+					   result-type circuit-file result-params))
+
+    ;; TODO deal with temporary files
+
+    ;;(org-babel-eval "ngspice -b " body)
+    ;; Write body to temp file & execute with ngspice comint buffer and ~source file~
+
+
+    ;; TODO read outputs from files
+
+    ;; TODO gnuplot options
+    (if (string= "yes" gnuplot)
+        nil ;return content(!) of gnuplot.plt for :post processing with gnuplot block?
+      nil ;return normal spice output
+      )
+    result
+    ))
+(defun org-babel-spice-source (buffer file)
+  "Source FILE in ngspice process running in BUFFER and return results."
+  (let ((body (concat "source " file)))
+    (org-babel-spice-evaluate buffer body 'value)))
+(defun org-babel-spice-evaluate (buffer body result-type &optional file result-params)
+  "Use BUFFER running ngspice process to eval BODY and return results.
+If RESULT-TYPE equals `output' return all outputs, if it equals
+`value' return only value of last statement.  FILE can refer to a
+spice input file that is sourced before BODY execution is started."
+  (let ((eoe-string (format "echo \"%s\"" org-babel-spice-eoe-indicator))
+	(eval-body (if file (concat "source " file "\n" body) "")))
+    (pcase result-type
+      (`output
+       ;; Force session to be ready
+       ;;(org-babel-comint-with-output
+       ;;    (buffer org-babel-spice-eoe-indicator t eoe-string)
+       ;;  (insert eoe-string) (comint-send-input nil t))
+       ;; Eval body
+       (org-babel-chomp
+	(replace-regexp-in-string
+	 "^Current directory: .*\n" ""
+	 (replace-regexp-in-string
+	  "^\\(ngspice [0-9]+ -> *\n*\\)*" ""
+	  (mapconcat
+	   #'identity
+	   (butlast
+	    (cdr
+	     (split-string
+	      (mapconcat
+	       #'org-trim
+	       (org-babel-comint-with-output (buffer org-babel-spice-eoe-indicator t eval-body)
+		 (mapcar (lambda (line)
+			   (insert (org-babel-chomp line)) (comint-send-input nil t))
+			 (list eval-body
+			       eoe-string
+			       "\n")))
+	       "\n") "[\r\n]")) 2) "\n"))))
+       )
+      (`value
+       (let ((tmp-file (org-babel-temp-file "spice-")))
+	 (org-babel-comint-with-output
+	     (buffer org-babel-spice-eoe-indicator t eval-body)
+	   (mapcar
+	    (lambda (line)
+	      (insert (org-babel-chomp line)) (comint-send-input nil t))
+	    (append (list eval-body)
+		    (list (format "echo !! > %s" tmp-file)
+			  (format "echo \"%s\"" org-babel-spice-eoe-indicator)
+			  )))
+	   (comint-send-input nil t))
+	 ;; split result to output multiple comma separated vars as table
+	 (let ((result (org-babel-spice-cleanup-result
+			(org-babel-chomp
+			 (org-babel-eval-read-file tmp-file)))))
+	   (if (or (not (listp result)) (cdr result))
+	       result
+	     (car result))
+	   )))
+      ;;todo: add "smart" result type to display measurements (or echos?) & plot filenames
+      )))
+(defun org-babel-spice-cleanup-result (result)
+  "Cleanup value to return instead of RESULT.
+Commands that write to files return the filename."
+  (let* ((index (if (string-match "^ *[^ ]*" result)
+		    (match-end 0) 0))
+	 (type (substring result 0 index))
+	 (arg (replace-regexp-in-string "^ *[^ ]* \\([^ ]*\\).*" "\\1" result)))
+    (message type)
+    (message arg)
+    (pcase type
+      ((or "wrdata" "write") arg)
+      ("gnuplot" (format "%s.png" arg))
+      ("echo" (split-string (substring result (+ index 1)) ","))
+      (_ result))))
+
+      (provide 'ob-spice)
+;;; ob-spice.el ends here
diff --git a/ob-spice.org b/ob-spice.org
deleted file mode 100644
index e162894..0000000
--- a/ob-spice.org
+++ /dev/null
@@ -1,671 +0,0 @@
-#+PROPERTY: header-args:emacs-lisp :tangle ob-spice.el :results silent
-#+PROPERTY: header-args:org :tangle readme.org :results silent
-* License
-#+BEGIN_SRC emacs-lisp
-  ;;; ob-spice.el --- Babel Functions for spice
-  ;;; -*- coding: utf-8 -*-
-
-  ;; License: GPL v3, or any later version
-  ;;
-  ;; This file is free software; you can redistribute it and/or modify
-  ;; it under the terms of the GNU General Public License as published by
-  ;; the Free Software Foundation; either version 3, or (at your option)
-  ;; any later version.
-  ;;
-  ;; This file is distributed in the hope that it will be useful,
-  ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  ;; GNU General Public License for more details.
-  ;;
-  ;; You should have received a copy of the GNU General Public License
-  ;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-  ;;; Commentary:
-
-  ;; Org-Babel support for evaluating spice.
-
-  ;;; Requirements:
-
-  ;; - ngspice :: http://ngspice.sourceforge.net/
-
-  ;;; Code:
-
-  (require 'ob)
-#+END_SRC
-* Auto-tangle
-#+BEGIN_SRC emacs-lisp :tangle no
-(defun my/tangle-ob-spice ()
-  "If the current file is '~/.emacs.d/lisp/ob-spice/ob-spice.org', the code blocks are tangled"
-  (when (equal buffer-file-name (concat (getenv "HOME") "/.emacs.d/lisp/ob-spice/ob-spice.org"))
-    (org-babel-tangle)
-    (message "%s tangled" buffer-file-name)))
-
-(add-hook 'after-save-hook #'my/tangle-ob-spice)
-#+END_SRC
-* Functionality
-
-- Temporary files in working directory are accepted (as they are
-  common in ngspice)
-- With no :file specified try to direct all outputs to a /tmp directory
-- option to return content of generated gnuplot .plt for easy use with
-  :post {generic gnuplot block}
-  - Full .plt or just data points?
-** Use cases
-*** DONE just load some circuit
-#+BEGIN_SRC spice :results output
-,* RC
-r1 1 0 10k
-c1 1 0 1p
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-#+END_SRC
-
-#+RESULTS:
-: Circuit: * rc
-
-*** DONE execute some stuff
-#+BEGIN_SRC spice
-echo "Hello world"
-#+END_SRC
-#+RESULTS:
-: Hello world
-
-#+BEGIN_SRC spice
-echo "0,1,2,3"
-#+END_SRC
-#+RESULTS:
-| 0 | 1 | 2 | 3 |
-
-
-*** DONE plot some voltages and return png
-#+BEGIN_SRC spice :var file="/tmp/xzy" :results file
-,*RC circuit
-r1 1 0 10k
-c1 1 0 1p
-
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-
-.control
-run
-set gnuplot_terminal=png
-gnuplot $file v(1)
-.endc
-#+END_SRC
-#+RESULTS:
-[[file:/tmp/xzy.png]]
-
-*** DONE do measurements and return results
-#+BEGIN_SRC spice :session spicetest :results value
-,*Time Constant Measurement
-r1 1 0 10k
-c1 1 0 1p
-
-.IC V(1)=1
-.tran 1n 0.1u
-.print tran v(1)
-.end
-
-.control
-run
-meas tran value_at_tau find V(1) at=1e-8
-meas tran value_at_five_tau find V(1) at=5e-8
-echo $&value_at_tau ,$&value_at_five_tau
-.endc
-#+END_SRC
-#+RESULTS:
-| 0.36798 | 0.00671732 |
-
-*** DONE write simulation data to file and return file name(s?)
-#+BEGIN_SRC spice :var file="/tmp/xyz" :results file :post plot_stuff(data=*this*)
-,*RC circuit
-r1 1 0 10k
-c1 1 0 1p
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-.control
-run
-wrdata $file v(1)
-.endc
-#+END_SRC 
-#+RESULTS:
-[[file:/tmp/xyz_plot.png]]
-
-#+NAME: plot_stuff
-#+BEGIN_SRC gnuplot :var data="x" :file "/tmp/xyz_plot.png" :results silent
-load '~/.gnuplot_settings.plt'
-plot data u 1:2 w l ls 1
-#+END_SRC
-
-** [1/6] Flags
-*** NEXT [#C] :netlist / :circuit
-Name of src block to include for netlist
-*** DONE [#B] :dir
-working directory to start ngspice in
-*** NEXT [#B] :file?
-default filename to use for 
-*** NEXT :gnuplot
-name of gnuplot block or .plt file: handle plotting instead of gnuplot
-lines
-*** NEXT :output
-**** `smart
-display measurements (or echos?) & plot filenames
-*** NEXT :batch / :no-interactive
-use batch mode
-** DONE Variable replacement in spice body
-** INPROGRESS Execution using ngspice
-*** NEXT Steps to using interactive mode
-- Output to a rawfile dumps all node data: ~ngspice -b -r x.raw
-  y.cir~. Can be loaded in interactive mode with ~load filename~.
-- Run file in interactive mode syncronously ~source input-file~ or
-  asyncronously ~aspice input-file~
-**** Comint mode to run ngspice in a buffer
-#+BEGIN_SRC emacs-lisp
-  (make-comint "spice" "ngspice")
-#+END_SRC
-** PLANNING (Auto-)Plotting
-* Readme.org
-#+BEGIN_SRC org
-,* Overview
-
-Extends org-babel capabilities to support spice simulations using
-ngspice. Simulations are executed using an interactive ngspice process
-running in emacs. The running ngspice process can be used to
-manipulate the simulation results directly or spread a simulation into
-multiple src blocks.
-
-Spice source blocks are interpreted as circuit descriptions until an
-'.end' line is encountered. After that a control part may follow
-(surrounded by '.control' and '.endc' lines). *If there is no '.end'*
-,*line all of the src block is interpreted as a control block!*
-
-,* Use cases
-,*** Just load some circuit for later simulation:
-,#+BEGIN_SRC spice :results output
-,,* RC
-r1 1 0 10k
-c1 1 0 1p
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-,#+END_SRC
-,#+RESULTS:
-: Circuit: * rc
-
-,*** Execute some stuff
-,#+BEGIN_SRC spice
-echo "Hello world"
-,#+END_SRC
-,#+RESULTS:
-: Hello world
-
-,#+BEGIN_SRC spice
-echo "0,1,2,3"
-,#+END_SRC
-,#+RESULTS:
-| 0 | 1 | 2 | 3 |
-
-,*** Plot some voltages and return png
-,#+BEGIN_SRC spice :var file="/tmp/xzy" :results file
-,,*RC circuit
-r1 1 0 10k
-c1 1 0 1p
-
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-
-.control
-run
-set gnuplot_terminal=png
-gnuplot $file v(1)
-.endc
-,#+END_SRC
-
-,#+RESULTS:
-[[file:/tmp/xzy.png]]
-
-,*** Do measurements and return results
-,#+BEGIN_SRC spice :session spicetest :results value
-,,*Time Constant Measurement
-r1 1 0 10k
-c1 1 0 1p
-
-.IC V(1)=1
-.tran 1n 0.1u
-.print tran v(1)
-.end
-
-.control
-run
-meas tran value_at_tau find V(1) at=1e-8
-meas tran value_at_five_tau find V(1) at=5e-8
-echo $&value_at_tau ,$&value_at_five_tau
-.endc
-,#+END_SRC
-
-,#+RESULTS:
-| 0.36798 | 0.00671732 |
-
-,*** write simulation data to file and return file name
-,#+BEGIN_SRC spice :var file="/tmp/xyz" :post plot_stuff(data=*this*) :results file
-,,*RC circuit
-r1 1 0 10k
-c1 1 0 1p
-.IC V(1)=1
-.tran 1n 0.1u
-.end
-.control
-run
-wrdata $file v(1)
-.endc
-,#+END_SRC
-
-,#+RESULTS:
-[[file:/tmp/xyz_plot.png]]
-
-,#+NAME: plot_stuff
-,#+BEGIN_SRC gnuplot :var data="x" :file "/tmp/xyz_plot.png" :results silent
-plot data u 1:2 w l ls 1
-,#+END_SRC
-
-,* Flags
-,** :netlist / :circuit
-Name of a src block to include for netlist/circuit descriptions.
-,** :dir
-Working directory to run the src block in. Default is the value of `default-directory'.
-,** :file?
-
-,** :gnuplot
-Name of gnuplot block or .plt file: handle plotting instead of gnuplot
-lines
-,** :results
-Available result options are `value' which returns the output of the
- last expression, `output' which returns all output and `smart' which
- tries to only display echos and plot filenames.
-,** :batch / :no-interactive
-use batch mode
-#+END_SRC
-* Code
-
-#+BEGIN_SRC emacs-lisp :tangle no
-(add-to-list 'load-path "~/.emacs.d/lisp/ob-spice")
-#+END_SRC
-** vars
-#+BEGIN_SRC emacs-lisp
-(defvar org-babel-spice-eoe-indicator ":org_babel_spice_eoe"
-  "String to indicate that evaluation has completed.")
-#+END_SRC
-** Session handling
-#+BEGIN_SRC emacs-lisp
-(defvar org-babel-spice-command "ngspice"
-  "Name of command to use for executing ngspice.")
-(defun org-babel-spice-initiate-session (&optional session dir _params)
-  "Initiate a ngspice session.
-Create comint buffer SESSION running ngspice starting in
-default-directory or DIR if specified."
-  (let* ((sessionname (if (or (not session) (string= session "none"))
-                          "spice" session))
-         (session (make-comint sessionname org-babel-spice-command)))
-    (if (and dir (file-name-absolute-p dir))
-	;; absolute dir
-	(comint-simple-send session (format "cd %s" dir))
-      ;; relative dir
-      (comint-simple-send session (format "cd %s" default-directory))
-    session
-    )))
-(defun org-babel-prep-session:spice (session params)
-  "Prepare SESSION according to header arguments in PARAMS."
-  (let ((session (org-babel-spice-initiate-session session))
-        (var-lines (org-babel-variable-assignments:spice params)))
-    (org-babel-comint-in-buffer session
-      (sit-for .5) (goto-char (point-max))
-      (mapc (lambda (var)
-              (insert var) (comint-send-input nil t)
-              (org-babel-comint-wait-for-output session)
-              (sit-for .1) (goto-char (point-max))) var-lines))
-    session))
-(defun org-babel-load-session:spice (session body params)
-  "Load BODY into SESSION."
-  (save-window-excursion
-    (let ((buffer (org-babel-prep-session:spice session params)))
-      (with-current-buffer buffer
-        (goto-char (process-mark (get-buffer-process (current-buffer))))
-        (insert (org-babel-chomp body)))
-      buffer)))
-
-;; helper
-
-(defun org-babel-variable-assignments:spice (params)
-  "Return a list of spice statements to set the variables in PARAMS."
-  (mapcar
-   (lambda (pair)
-     (format "set %s=%s"
-             (car pair)
-             (org-babel-spice-var-to-spice (cdr pair))))
-   (org-babel--get-vars params)))
-(defun org-babel-spice-var-to-spice (var)
-  "Convert VAR into a spice variable."
-  (if (listp var)
-      (concat "( " (mapconcat #'org-babel-spice-var-to-spice var " ") " )")
-    (format "%S" var)))
-#+END_SRC
-** NEXT Variable handling & expand body
-Don't replace variable calls in body. Instead set them in the spice
-session: ~set x=4~\\
-~set~ only sets lowercase variants of words!
-
-To set lists/arrays: ~set x=( 1 2 3 4 )~. Whitespace is important!
-Access with ~$x[0]~ or ~$x[2-len]~.
-#+BEGIN_SRC emacs-lisp
-;; (lambda (text) (setq body (concat text "\n" body)))
-(defun org-babel-spice-vector-search (body vars)
-  "Replace first instance in BODY for all VARS."
-  (mapc (lambda (pair)
-          (if (string-match (format
-                             "\\$%s\\[\\([0-9]\\)\\]"
-                             (car pair))
-                            body)
-              (let ((replacement (nth
-                                  (string-to-number (match-string 1 body))
-                                  pair)))
-                (setq body(format "%s%s%s"
-                                  (substring body 0 (match-beginning
-                                                     0))
-                                  replacement
-                                  (substring body (match-end 0)))))))
-        vars)
-  body
-  )
-#+END_SRC
-#+BEGIN_SRC emacs-lisp
-(defun org-babel-spice-replace-vars (body vars)
-  "Expand BODY according to VARS."
-  (let ((old-body ""))
-    ;; replace vector variables preceded by '$' and followed by the
-    ;; index in square brackets starting at 0. Matches without
-    ;; preceding or succeeding spaces.
-    (while (not (string= old-body body))
-      (setq old-body body)
-      (setq body (org-babel-spice-vector-search body vars))
-      )
-    ;; replace any variable names preceded by '$' with the actual
-    ;; value of the variable. Matches only with succeeding space or
-    ;; end of line to prevent namespace limitations.
-    (mapc (lambda (pair)
-            (setq body (replace-regexp-in-string
-                        (format "\\$%s\\( \\)\\|\\$%s$" (car pair)
-                                (car pair))
-                        (format "%s\1" (cdr pair))
-                        body)))
-          vars)
-    body))
-(defun org-babel-expand-body:spice (body params)
-  "Expand BODY according to PARAMS, return the expanded body."
-  (let ((vars (org-babel--get-vars params))
-        (prologue (cdr (assq :prologue params)))
-        (epilogue (cdr (assq :epilogue params)))
-        (file (cdr (assq :file params))))
-    (setq body (org-babel-spice-replace-vars body vars))
-    ;; TODO :file stuff ....
-
-    ;; add prologue/epilogue
-    (when prologue (setq body (concat prologue "\n" body)))
-    (when epilogue (setq body (concat body "\n" epilogue)))
-    body))
-#+END_SRC
-** ob-execute
-#+BEGIN_SRC emacs-lisp
-(defun org-babel-spice-trim-body (body)
-  "Prepare BODY to be used in interactive ngspice session."
-  ;; random control codes after $var inserts
-  (replace-regexp-in-string
-   "
" " "
-   ;; .control .endc lines
-   (replace-regexp-in-string
-    "^ *\\.\\(control\\|endc\\) *$" ""
-    ;; comment lines
-    (replace-regexp-in-string
-     "^ *\\*.*$" "" body))))
-(defun org-babel-execute:spice (body params)
-  "Execute a block of Spice code with Babel.
-This function is called by `org-babel-execute-src-block'."
-  (let* (;(body (org-babel-expand-body:spice body params))
-         (gnuplot (cdr (assq :gnuplot params)))
-         (result-params (cdr (assq :result-params params)))
-         (result-type (cdr (assq :result-type params)))
-         (session (org-babel-spice-initiate-session
-                   (cdr (assq :session params))
-                   (cdr (assq :dir params))))
-         (vars (org-babel--get-vars params))
-         (no-source (cdr (assq :no-source params)))
-         (break-index (if (string-match "^ *\.end *$" body)
-                          (match-end 0) 0))
-         ;;vars need to be replaced as they don't work when using source
-         (circuit-body (org-babel-expand-body:spice
-                        (substring body 0 break-index)
-                        (assq-delete-all :epilogue (copy-alist params))))
-         ;; todo: replace vars. :-( → set vars break when doing something like $file.txt
-         (control-body (org-babel-spice-trim-body (substring body break-index)))
-         (full-control-body (if (not (string= control-body ""))
-				(org-babel-expand-body:generic
-				 control-body
-				 (assq-delete-all :prologue (copy-alist params))
-				 (org-babel-variable-assignments:spice params)) ""))
-         (circuit-file (if circuit-body (org-babel-temp-file "spice-body-" ".cir")))
-         (result))
-
-
-    (message (concat "circuit:\n" circuit-body))
-    (message (concat "\n-----\ncontrol:\n" control-body))
-
-    ;; Source circuit-body
-    (with-temp-file circuit-file (insert circuit-body))
-    ;; Evaluate
-    (setq result (org-babel-spice-evaluate session full-control-body
-					   result-type circuit-file result-params))
-
-    ;; TODO deal with temporary files
-
-    ;;(org-babel-eval "ngspice -b " body)
-    ;; Write body to temp file & execute with ngspice comint buffer and ~source file~
-
-
-    ;; TODO read outputs from files
-
-    ;; TODO gnuplot options
-    (if (string= "yes" gnuplot)
-        nil ;return content(!) of gnuplot.plt for :post processing with gnuplot block?
-      nil ;return normal spice output
-      )
-    result
-    ))
-(defun org-babel-spice-source (buffer file)
-  "Source FILE in ngspice process running in BUFFER and return results."
-  (let ((body (concat "source " file)))
-    (org-babel-spice-evaluate buffer body 'value)))
-(defun org-babel-spice-evaluate (buffer body result-type &optional file result-params)
-  "Use BUFFER running ngspice process to eval BODY and return results.
-If RESULT-TYPE equals `output' return all outputs, if it equals
-`value' return only value of last statement.  FILE can refer to a
-spice input file that is sourced before BODY execution is started."
-  (let ((eoe-string (format "echo \"%s\"" org-babel-spice-eoe-indicator))
-	(eval-body (if file (concat "source " file "\n" body) "")))
-    (pcase result-type
-      (`output
-       ;; Force session to be ready
-       ;;(org-babel-comint-with-output
-       ;;    (buffer org-babel-spice-eoe-indicator t eoe-string)
-       ;;  (insert eoe-string) (comint-send-input nil t))
-       ;; Eval body
-       (org-babel-chomp
-	(replace-regexp-in-string
-	 "^Current directory: .*\n" ""
-	 (replace-regexp-in-string
-	  "^\\(ngspice [0-9]+ -> *\n*\\)*" ""
-	  (mapconcat
-	   #'identity
-	   (butlast
-	    (cdr
-	     (split-string
-	      (mapconcat
-	       #'org-trim
-	       (org-babel-comint-with-output (buffer org-babel-spice-eoe-indicator t eval-body)
-		 (mapcar (lambda (line)
-			   (insert (org-babel-chomp line)) (comint-send-input nil t))
-			 (list eval-body
-			       eoe-string
-			       "\n")))
-	       "\n") "[\r\n]")) 2) "\n"))))
-       )
-      (`value
-       (let ((tmp-file (org-babel-temp-file "spice-")))
-	 (org-babel-comint-with-output
-	     (buffer org-babel-spice-eoe-indicator t eval-body)
-	   (mapcar
-	    (lambda (line)
-	      (insert (org-babel-chomp line)) (comint-send-input nil t))
-	    (append (list eval-body)
-		    (list (format "echo !! > %s" tmp-file)
-			  (format "echo \"%s\"" org-babel-spice-eoe-indicator)
-			  )))
-	   (comint-send-input nil t))
-	 ;; split result to output multiple comma separated vars as table
-	 (let ((result (org-babel-spice-cleanup-result
-			(org-babel-chomp
-			 (org-babel-eval-read-file tmp-file)))))
-	   (if (or (not (listp result)) (cdr result))
-	       result
-	     (car result))
-	   )))
-      ;;todo: add "smart" result type to display measurements (or echos?) & plot filenames
-      )))
-(defun org-babel-spice-cleanup-result (result)
-  "Cleanup value to return instead of RESULT.
-Commands that write to files return the filename."
-  (let* ((index (if (string-match "^ *[^ ]*" result)
-		    (match-end 0) 0))
-	 (type (substring result 0 index))
-	 (arg (replace-regexp-in-string "^ *[^ ]* \\([^ ]*\\).*" "\\1" result)))
-    (message type)
-    (message arg)
-    (pcase type
-      ((or "wrdata" "write") arg)
-      ("gnuplot" (format "%s.png" arg))
-      ("echo" (split-string (substring result (+ index 1)) ","))
-      (_ result))))
-
-      (provide 'ob-spice)
-;;; ob-spice.el ends here
-#+END_SRC
-
-* Tests
-#+BEGIN_SRC spice :var x="4" :session spicetest :no-source yes
-echo "Hello World"
-#+END_SRC
-
-#+RESULTS:
-: Hello World
-
-
-#+BEGIN_SRC spice :var file="/tmp/spice_test"  :session spicetest :results value
-,*Time Constant Measurement
-r1 1 0 10k
-c1 1 0 1p
-
-.IC V(1)=1
-.tran 1n 0.1u
-.print tran v(1)
-.end
-
-.control
-run
-set gnuplot_terminal=png
-,*gnuplot $file v(1)
-meas tran value_at_tau find V(1) at=1e-8
-meas tran value_at_five_tau find V(1) at=5e-8
-echo value_at_tau = "$&value_at_tau" > $file.txt
-,* Any better way to write one value of vector to a file??
-echo $&value_at_tau ,$&value_at_five_tau
-.endc
-#+END_SRC
-
-#+RESULTS:
-| 0.36798 | 0.00671732 |
-
-#+BEGIN_SRC spice :var file="/tmp/spice_test2" :session spicetest :results file
-,*Virtual Ground Test: opamp gain = 1000
-vin in 0 dc 0V sin(0 .1 100Hz)
-r1 in inn 10k
-r2 inn out 10k
-EOpamp out 0 0 inn 1000
-.tran 0.1ms 0.05s
-.print tran v(in)
-.meas tran vtest find v(in) at=0.04e-3
-.end
-.control
-run
-set gnuplot_terminal=png
-gnuplot $file v(in) v(out) v(inn)
-.endc
-#+END_SRC
-
-#+RESULTS:
-[[file:/tmp/spice_test2]]
-
-** advanced example
-#+NAME: dim1_params
-#+BEGIN_SRC ruby :exports none
-[7.3260073260073255e-06,1.3215597400496679e-05,5.411787135503391e-06,2.344322344322345e-05,2.4e-06, 100.0]
-#+END_SRC
-#+RESULTS: dim1_params
-| 7.3260073260073255e-06 | 1.3215597400496679e-05 | 5.411787135503391e-06 | 2.344322344322345e-05 | 2.4e-06 | 100.0 |
-
-#+NAME: dim1_plot
-#+BEGIN_SRC gnuplot :var data="x" :file /tmp/ignored.png :results silent :exports none
- set terminal pngcairo size 640,300 enhanced
- set format y "%.0s%cV"
- set format x "%.0s%cs"
- set xrange [190e-9:260e-9]
- set ytics 5e-3
- set xlabel "t"
- plot data using 1:2 w l ls 2 t "V_{out}"
-#+END_SRC
-
-#+BEGIN_SRC spice :session test :var dim=dim1_params :results output
-,* DAC.asc
-.model NMOS NMOS
-.model PMOS PMOS
-.lib /home/fred/spice/library/ngspice/CM5/CM5-N.phy CM5
-M1 0 VDD N005 N005 MP7 l= $dim[5] w= $dim[4]
-M2 VOUT VCTRL N005 N005 MP7 l= $dim[5] w= $dim[4]
-M4 N003 N002 VDD VDD MP7 l= $dim[3] w= $dim[2]
-M3 N002 N002 VDD VDD MP7 l= $dim[3] w= $dim[2]
-M5 N005 N004 N003 N003 MP7 l= $dim[3] w= $dim[2]
-M6 N004 N004 N002 N002 MP7 l= $dim[3] w= $dim[2]
-RL VOUT 0 $dim[6]
-CL VOUT 0 10p
-VDD VDD 0 5
-IREF N004 0 7.3u
-V1 VBIAS 0 2.5
-V2 VCTRL 0 PULSE(0 5 0 1n 1n 200n 420n)
-VM VDD N001 0
-.tran 1n 300n 190n
-.end
-#+END_SRC
-
-#+RESULTS:
-: Circuit: * dac.asc
-
-#+NAME: dim1
-#+BEGIN_SRC spice :session test :var file="/tmp/dim1" dim=dim1_params :post dim1_plot[:file /tmp/dim1.png](data=*this*) :results file
-save all
-run
-wrdata $file v(vout)
-#+END_SRC
-
-#+RESULTS: dim1
-[[file:/tmp/dim1.png]]
diff --git a/readme.org b/readme.org
new file mode 100644
index 0000000..b193b88
--- /dev/null
+++ b/readme.org
@@ -0,0 +1,119 @@
+* Overview
+
+Extends org-babel capabilities to support spice simulations using
+ngspice. Simulations are executed using an interactive ngspice process
+running in emacs. The running ngspice process can be used to
+manipulate the simulation results directly or spread a simulation into
+multiple src blocks.
+
+Spice source blocks are interpreted as circuit descriptions until an
+'.end' line is encountered. After that a control part may follow
+(surrounded by '.control' and '.endc' lines). *If there is no '.end'*
+*line all of the src block is interpreted as a control block!*
+
+* Use cases
+*** Just load some circuit for later simulation:
+#+BEGIN_SRC spice :results output
+,* RC
+r1 1 0 10k
+c1 1 0 1p
+.IC V(1)=1
+.tran 1n 0.1u
+.end
+#+END_SRC
+#+RESULTS:
+: Circuit: * rc
+
+*** Execute some stuff
+#+BEGIN_SRC spice
+echo "Hello world"
+#+END_SRC
+#+RESULTS:
+: Hello world
+
+#+BEGIN_SRC spice
+echo "0,1,2,3"
+#+END_SRC
+#+RESULTS:
+| 0 | 1 | 2 | 3 |
+
+*** Plot some voltages and return png
+#+BEGIN_SRC spice :var file="/tmp/xzy" :results file
+,*RC circuit
+r1 1 0 10k
+c1 1 0 1p
+
+.IC V(1)=1
+.tran 1n 0.1u
+.end
+
+.control
+run
+set gnuplot_terminal=png
+gnuplot $file v(1)
+.endc
+#+END_SRC
+
+#+RESULTS:
+[[file:/tmp/xzy.png]]
+
+*** Do measurements and return results
+#+BEGIN_SRC spice :session spicetest :results value
+,*Time Constant Measurement
+r1 1 0 10k
+c1 1 0 1p
+
+.IC V(1)=1
+.tran 1n 0.1u
+.print tran v(1)
+.end
+
+.control
+run
+meas tran value_at_tau find V(1) at=1e-8
+meas tran value_at_five_tau find V(1) at=5e-8
+echo $&value_at_tau ,$&value_at_five_tau
+.endc
+#+END_SRC
+
+#+RESULTS:
+| 0.36798 | 0.00671732 |
+
+*** write simulation data to file and return file name
+#+BEGIN_SRC spice :var file="/tmp/xyz" :post plot_stuff(data=*this*) :results file
+,*RC circuit
+r1 1 0 10k
+c1 1 0 1p
+.IC V(1)=1
+.tran 1n 0.1u
+.end
+.control
+run
+wrdata $file v(1)
+.endc
+#+END_SRC
+
+#+RESULTS:
+[[file:/tmp/xyz_plot.png]]
+
+#+NAME: plot_stuff
+#+BEGIN_SRC gnuplot :var data="x" :file "/tmp/xyz_plot.png" :results silent
+plot data u 1:2 w l ls 1
+#+END_SRC
+
+* Flags
+** :netlist / :circuit
+Name of a src block to include for netlist/circuit descriptions.
+** :dir
+Working directory to run the src block in. Default is the value of `default-directory'.
+** :file?
+
+** :gnuplot
+Name of gnuplot block or .plt file: handle plotting instead of gnuplot
+lines
+** :results
+Available result options are `value' which returns the output of the
+ last expression, `output' which returns all output and `smart' which
+ tries to only display echos and plot filenames.
+** :batch / :no-interactive
+use batch mode