diff --git a/docs/book.toml b/docs/book.toml
index 742e7869..0f920356 100644
--- a/docs/book.toml
+++ b/docs/book.toml
@@ -13,7 +13,7 @@ title = "Rustemo book"
 
 [output.html]
 additional-css = ["./mdbook-admonish.css", "theme/pagetoc.css"] #, "style.css"]
-additional-js = ["theme/pagetoc.js"] # , "sidebar.js"]
+additional-js = ["theme/pagetoc.js"]                            # , "sidebar.js"]
 
 # [output.pandoc.profile.pdf]
 # output-file = "Rustemo.pdf"
@@ -36,24 +36,25 @@ warning-policy = "error"
 [preprocessor]
 
 [preprocessor.theme]
-turn-off = true         # Comment this line and run `mdbook build` when theme is changed
-pagetoc        = true
-pagetoc-width            = "13%"
-content-max-width        = "85%"
-pagetoc-fontsize         = "14.5px"
-sidebar-width            = "300px"
+turn-off = true             # Comment this line and run `mdbook build` when theme is changed
+pagetoc = true
+pagetoc-width = "13%"
+content-max-width = "85%"
+pagetoc-fontsize = "14.5px"
+sidebar-width = "300px"
 
 
 [preprocessor.admonish]
 command = "mdbook-admonish"
-assets_version = "3.0.1" # do not edit: managed by `mdbook-admonish install`
+assets_version = "3.0.1"    # do not edit: managed by `mdbook-admonish install`
 
 # [preprocessor.bib]
 # bibliography = "references.bib"
 
 [preprocessor.plantuml]
+plantuml-cmd = "plantuml"
 
 [preprocessor.graphviz]
 after = ["links"]
 output-to-file = true # defaults to false, change to true to create SVG files
-                      # instead of rendering them inline
+# instead of rendering them inline
diff --git a/docs/src/mdbook-plantuml-img/9e65b16f38683a44d16aea04a658fdc1c24886d4.svg b/docs/src/mdbook-plantuml-img/9e65b16f38683a44d16aea04a658fdc1c24886d4.svg
index defe9bab..3c4ebb6e 100644
--- a/docs/src/mdbook-plantuml-img/9e65b16f38683a44d16aea04a658fdc1c24886d4.svg
+++ b/docs/src/mdbook-plantuml-img/9e65b16f38683a44d16aea04a658fdc1c24886d4.svg
@@ -1 +1 @@
-<?xml version="1.0" encoding="us-ascii" standalone="no"?><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" contentStyleType="text/css" height="336px" preserveAspectRatio="none" style="width:326px;height:336px;background:#FFFFFF;" version="1.1" viewBox="0 0 326 336" width="326px" zoomAndPan="magnify"><defs/><g><rect fill="none" height="193.2361" style="stroke:#000000;stroke-width:1.5;" width="310.5" x="10" y="56.0679"/><rect fill="none" height="96.118" style="stroke:#000000;stroke-width:1.5;" width="290.5" x="20" y="82.7739"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="58" x2="58" y1="39.0679" y2="298.01"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="202.5" x2="202.5" y1="39.0679" y2="298.01"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="268.5" x2="268.5" y1="39.0679" y2="298.01"/><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="57" x="30" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="43" x="37" y="26.9659">Parser</text><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="57" x="30" y="297.01"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="43" x="37" y="318.976">Parser</text><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="50" x="177.5" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="36" x="184.5" y="26.9659">Lexer</text><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="50" x="177.5" y="297.01"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="36" x="184.5" y="318.976">Lexer</text><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="63" x="237.5" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="49" x="244.5" y="26.9659">Builder</text><rect fill="#E2E2F0" height="33.0679" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="63" x="237.5" y="297.01"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="49" x="244.5" y="318.976">Builder</text><path d="M10,56.0679 L83,56.0679 L83,65.7739 L73,75.7739 L10,75.7739 L10,56.0679 " fill="#EEEEEE" style="stroke:#000000;stroke-width:1.5;"/><rect fill="none" height="193.2361" style="stroke:#000000;stroke-width:1.5;" width="310.5" x="10" y="56.0679"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacing" textLength="28" x="25" y="70.9649">loop</text><text fill="#000000" font-family="sans-serif" font-size="11" font-weight="bold" lengthAdjust="spacing" textLength="124" x="98" y="69.8268">[until no more tokens]</text><path d="M20,82.7739 L93,82.7739 L93,92.4799 L83,102.4799 L20,102.4799 L20,82.7739 " fill="#EEEEEE" style="stroke:#000000;stroke-width:1.5;"/><rect fill="none" height="96.118" style="stroke:#000000;stroke-width:1.5;" width="290.5" x="20" y="82.7739"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacing" textLength="28" x="35" y="97.6709">loop</text><text fill="#000000" font-family="sans-serif" font-size="11" font-weight="bold" lengthAdjust="spacing" textLength="159" x="108" y="96.5328">[until reduction not possible]</text><line style="stroke:#181818;stroke-width:1.0;" x1="58.5" x2="100.5" y1="126.186" y2="126.186"/><line style="stroke:#181818;stroke-width:1.0;" x1="100.5" x2="100.5" y1="126.186" y2="139.186"/><line style="stroke:#181818;stroke-width:1.0;" x1="59.5" x2="100.5" y1="139.186" y2="139.186"/><polygon fill="#181818" points="69.5,135.186,59.5,139.186,69.5,143.186,65.5,139.186" style="stroke:#181818;stroke-width:1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="44" x="65.5" y="120.377">Reduce</text><polygon fill="#181818" points="257,166.892,267,170.892,257,174.892,261,170.892" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="58.5" x2="263" y1="170.892" y2="170.892"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="134" x="65.5" y="165.083">Execute Reduce action</text><polygon fill="#181818" points="190.5,205.598,200.5,209.598,190.5,213.598,194.5,209.598" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="58.5" x2="196.5" y1="209.598" y2="209.598"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="120" x="65.5" y="203.789">Shift/get next token</text><polygon fill="#181818" points="257,237.304,267,241.304,257,245.304,261,241.304" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="58.5" x2="263" y1="241.304" y2="241.304"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="117" x="65.5" y="235.495">Execute Shift action</text><polygon fill="#181818" points="257,276.01,267,280.01,257,284.01,261,280.01" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="58.5" x2="263" y1="280.01" y2="280.01"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="105" x="65.5" y="274.201">Get build product</text></g></svg>
\ No newline at end of file
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" contentStyleType="text/css" height="312px" preserveAspectRatio="none" style="width:332px;height:312px;background:#FFFFFF;" version="1.1" viewBox="0 0 332 312" width="332px" zoomAndPan="magnify"><defs/><g><rect fill="none" height="177.7969" style="stroke:#000000;stroke-width:1.5;" width="316.5" x="10" y="53.2969"/><rect fill="none" height="88.3984" style="stroke:#000000;stroke-width:1.5;" width="296.5" x="20" y="77.4297"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="59" x2="59" y1="36.2969" y2="277.2266"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="208.5" x2="208.5" y1="36.2969" y2="277.2266"/><line style="stroke:#181818;stroke-width:0.5;stroke-dasharray:5.0,5.0;" x1="275.5" x2="275.5" y1="36.2969" y2="277.2266"/><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="58" x="30" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="44" x="37" y="24.9951">Parser</text><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="58" x="30" y="276.2266"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="44" x="37" y="296.2217">Parser</text><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="51" x="183.5" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="37" x="190.5" y="24.9951">Lexer</text><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="51" x="183.5" y="276.2266"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="37" x="190.5" y="296.2217">Lexer</text><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="62" x="244.5" y="5"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="48" x="251.5" y="24.9951">Builder</text><rect fill="#E2E2F0" height="30.2969" rx="2.5" ry="2.5" style="stroke:#181818;stroke-width:0.5;" width="62" x="244.5" y="276.2266"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacing" textLength="48" x="251.5" y="296.2217">Builder</text><path d="M10,53.2969 L83.625,53.2969 L83.625,60.4297 L73.625,70.4297 L10,70.4297 L10,53.2969 " fill="#EEEEEE" style="stroke:#000000;stroke-width:1.5;"/><rect fill="none" height="177.7969" style="stroke:#000000;stroke-width:1.5;" width="316.5" x="10" y="53.2969"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacing" textLength="28.625" x="25" y="66.3638">loop</text><text fill="#000000" font-family="sans-serif" font-size="11" font-weight="bold" lengthAdjust="spacing" textLength="132.5313" x="98.625" y="65.5073">[until no more tokens]</text><path d="M20,77.4297 L93.625,77.4297 L93.625,84.5625 L83.625,94.5625 L20,94.5625 L20,77.4297 " fill="#EEEEEE" style="stroke:#000000;stroke-width:1.5;"/><rect fill="none" height="88.3984" style="stroke:#000000;stroke-width:1.5;" width="296.5" x="20" y="77.4297"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacing" textLength="28.625" x="35" y="90.4966">loop</text><text fill="#000000" font-family="sans-serif" font-size="11" font-weight="bold" lengthAdjust="spacing" textLength="172.2813" x="108.625" y="89.6401">[until reduction not possible]</text><line style="stroke:#181818;stroke-width:1.0;" x1="59" x2="101" y1="115.6953" y2="115.6953"/><line style="stroke:#181818;stroke-width:1.0;" x1="101" x2="101" y1="115.6953" y2="128.6953"/><line style="stroke:#181818;stroke-width:1.0;" x1="60" x2="101" y1="128.6953" y2="128.6953"/><polygon fill="#181818" points="70,124.6953,60,128.6953,70,132.6953,66,128.6953" style="stroke:#181818;stroke-width:1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="47" x="66" y="110.6294">Reduce</text><polygon fill="#181818" points="263.5,153.8281,273.5,157.8281,263.5,161.8281,267.5,157.8281" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="59" x2="269.5" y1="157.8281" y2="157.8281"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="145" x="66" y="152.7622">Execute Reduce action</text><polygon fill="#181818" points="197,189.9609,207,193.9609,197,197.9609,201,193.9609" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="59" x2="203" y1="193.9609" y2="193.9609"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="126" x="66" y="188.895">Shift/get next token</text><polygon fill="#181818" points="263.5,219.0938,273.5,223.0938,263.5,227.0938,267.5,223.0938" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="59" x2="269.5" y1="223.0938" y2="223.0938"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="127" x="66" y="218.0278">Execute Shift action</text><polygon fill="#181818" points="263.5,255.2266,273.5,259.2266,263.5,263.2266,267.5,259.2266" style="stroke:#181818;stroke-width:1.0;"/><line style="stroke:#181818;stroke-width:1.0;" x1="59" x2="269.5" y1="259.2266" y2="259.2266"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacing" textLength="110" x="66" y="254.1606">Get build product</text></g></svg>
\ No newline at end of file