Change: keep actual text of keyword from scenario

The typesetting should preserve the actual keyword or alias in the
source. Previously, if source had this:

```
given foo
and bar
```

it got typeset as if were:

```
given foo
given bar
```

Also, change subplot.md to use alias when possible.

6 files changed, 158 insertions, 113 deletions

diff --git a/src/ast.rs b/src/ast.rs
index 27401ad..962aa21 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -785,12 +785,7 @@ fn step(
 // Typeset first word, which is assumed to be a keyword, of a scenario
 // step.
 fn keyword(step: &ScenarioStep) -> Inline {
-    let word = match step.kind() {
-        StepKind::Given => "given",
-        StepKind::When => "when",
-        StepKind::Then => "then",
-    };
-    let word = inlinestr(word);
+    let word = inlinestr(step.keyword());
     Inline::Emph(vec![word])
 }
 
diff --git a/src/bindings.rs b/src/bindings.rs
index d53df23..30e7df9 100644
--- a/src/bindings.rs
+++ b/src/bindings.rs
@@ -163,21 +163,21 @@ mod test_binding {
 
     #[test]
     fn does_not_match_with_wrong_kind() {
-        let step = ScenarioStep::new(StepKind::Given, "yo");
+        let step = ScenarioStep::new(StepKind::Given, "given", "yo");
         let b = Binding::new(StepKind::When, "yo", "do_yo").unwrap();
         assert!(b.match_with_step(&step).is_none());
     }
 
     #[test]
     fn does_not_match_with_wrong_text() {
-        let step = ScenarioStep::new(StepKind::Given, "foo");
+        let step = ScenarioStep::new(StepKind::Given, "given", "foo");
         let b = Binding::new(StepKind::Given, "bar", "yo").unwrap();
         assert!(b.match_with_step(&step).is_none());
     }
 
     #[test]
     fn match_with_fixed_pattern() {
-        let step = ScenarioStep::new(StepKind::Given, "foo");
+        let step = ScenarioStep::new(StepKind::Given, "given", "foo");
         let b = Binding::new(StepKind::Given, "foo", "do_foo").unwrap();
         let m = b.match_with_step(&step).unwrap();
         assert_eq!(m.kind(), StepKind::Given);
@@ -189,7 +189,7 @@ mod test_binding {
 
     #[test]
     fn match_with_regex() {
-        let step = ScenarioStep::new(StepKind::Given, "I am Tomjon, I am");
+        let step = ScenarioStep::new(StepKind::Given, "given", "I am Tomjon, I am");
         let b = Binding::new(StepKind::Given, r"I am (?P<who>\S+), I am", "set_name").unwrap();
         let m = b.match_with_step(&step).unwrap();
         assert_eq!(m.kind(), StepKind::Given);
@@ -388,7 +388,7 @@ mod test_bindings {
 
     #[test]
     fn does_not_find_match_for_unmatching_kind() {
-        let step = ScenarioStep::new(StepKind::Given, "I am Tomjon");
+        let step = ScenarioStep::new(StepKind::Given, "given", "I am Tomjon");
         let binding = Binding::new(StepKind::When, r"I am Tomjon", "set_foo").unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
@@ -397,7 +397,7 @@ mod test_bindings {
 
     #[test]
     fn does_not_find_match_for_unmatching_pattern() {
-        let step = ScenarioStep::new(StepKind::Given, "I am Tomjon");
+        let step = ScenarioStep::new(StepKind::Given, "given", "I am Tomjon");
         let binding = Binding::new(StepKind::Given, r"I am Tomjon of Lancre", "set_foo").unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
@@ -406,7 +406,7 @@ mod test_bindings {
 
     #[test]
     fn finds_match_for_fixed_string_pattern() {
-        let step = ScenarioStep::new(StepKind::Given, "I am Tomjon");
+        let step = ScenarioStep::new(StepKind::Given, "given", "I am Tomjon");
         let binding = Binding::new(StepKind::Given, r"I am Tomjon", "set_name").unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
@@ -423,7 +423,7 @@ mod test_bindings {
 
     #[test]
     fn finds_match_for_regexp_pattern() {
-        let step = ScenarioStep::new(StepKind::Given, "I am Tomjon");
+        let step = ScenarioStep::new(StepKind::Given, "given", "I am Tomjon");
         let binding = Binding::new(StepKind::Given, r"I am (?P<name>\S+)", "set_name").unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
diff --git a/src/error.rs b/src/error.rs
index 3d28d3b..0a79cf6 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -89,15 +89,19 @@ pub enum SubplotError {
     #[error("first scenario is before first heading")]
     ScenarioBeforeHeading,
 
-    /// Unknown scenario step keyword
+    /// Step does not have a keyword.
+    #[error("step has no keyword: {0}")]
+    NoStepKeyword(String),
+
+    /// Unknown scenario step keyword.
     ///
     /// Each scenario step must start with a known keyword (given,
     /// when, then, and, but), but Subplot didn't find one it
     /// recognized.
     ///
     /// This is usually due to a typing mistake or similar.
-    #[error("unknown step keyword")]
-    UnknownStepKind,
+    #[error("unknown step keyword: {0}")]
+    UnknownStepKind(String),
 
     /// Scenario step uses continuation keyword too early
     ///
diff --git a/src/scenarios.rs b/src/scenarios.rs
index 569d33a..bb1e3df 100644
--- a/src/scenarios.rs
+++ b/src/scenarios.rs
@@ -94,7 +94,7 @@ mod test {
     #[test]
     fn adds_step() {
         let mut scen = Scenario::new("title");
-        let step = ScenarioStep::new(StepKind::Given, "foo");
+        let step = ScenarioStep::new(StepKind::Given, "and", "foo");
         scen.add(&step);
         assert_eq!(scen.steps(), &[step]);
     }
diff --git a/src/steps.rs b/src/steps.rs
index 2c6f34f..1cbdfe5 100644
--- a/src/steps.rs
+++ b/src/steps.rs
@@ -14,14 +14,16 @@ use std::fmt;
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub struct ScenarioStep {
     kind: StepKind,
+    keyword: String,
     text: String,
 }
 
 impl ScenarioStep {
     /// Construct a new step.
-    pub fn new(kind: StepKind, text: &str) -> ScenarioStep {
+    pub fn new(kind: StepKind, keyword: &str, text: &str) -> ScenarioStep {
         ScenarioStep {
             kind,
+            keyword: keyword.to_owned(),
             text: text.to_owned(),
         }
     }
@@ -31,6 +33,11 @@ impl ScenarioStep {
         self.kind
     }
 
+    /// Return the actual textual keyword of a step.
+    pub fn keyword(&self) -> &str {
+        &self.keyword
+    }
+
     /// Return the text of a step.
     pub fn text(&self) -> &str {
         &self.text
@@ -43,13 +50,18 @@ impl ScenarioStep {
     pub fn new_from_str(text: &str, default: Option<StepKind>) -> Result<ScenarioStep> {
         let mut words = text.split_whitespace();
 
-        let kind = match words.next() {
-            Some("given") => StepKind::Given,
-            Some("when") => StepKind::When,
-            Some("then") => StepKind::Then,
-            Some("and") => default.ok_or(SubplotError::ContinuationTooEarly)?,
-            Some("but") => default.ok_or(SubplotError::ContinuationTooEarly)?,
-            _ => return Err(SubplotError::UnknownStepKind),
+        let keyword = match words.next() {
+            Some(s) => s,
+            _ => return Err(SubplotError::NoStepKeyword(text.to_string())),
+        };
+
+        let kind = match keyword {
+            "given" => StepKind::Given,
+            "when" => StepKind::When,
+            "then" => StepKind::Then,
+            "and" => default.ok_or(SubplotError::ContinuationTooEarly)?,
+            "but" => default.ok_or(SubplotError::ContinuationTooEarly)?,
+            _ => return Err(SubplotError::UnknownStepKind(keyword.to_string())),
         };
 
         let mut joined = String::new();
@@ -60,13 +72,13 @@ impl ScenarioStep {
         if joined.len() > 1 {
             joined.pop();
         }
-        Ok(ScenarioStep::new(kind, &joined))
+        Ok(ScenarioStep::new(kind, keyword, &joined))
     }
 }
 
 impl fmt::Display for ScenarioStep {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{} {}", self.kind(), self.text())
+        write!(f, "{} {}", self.keyword(), self.text())
     }
 }
 
diff --git a/subplot.md b/subplot.md
index 7b42dea..b73effa 100644
--- a/subplot.md
+++ b/subplot.md
@@ -518,18 +518,18 @@ program, and examining the output.
 
 ~~~scenario
 given file simple.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen simple.md -o simple.pdf
 then file simple.pdf exists
 when I run sp-docgen simple.md -o simple.html
 then file simple.html exists
 when I run sp-codegen --run simple.md -o test.py
 then scenario "Simple" was run
-then step "given precondition foo" was run
-then step "when I do bar" was run
-then step "then bar was done" was run
-then program finished successfully
+and step "given precondition foo" was run
+and step "when I do bar" was run
+and step "then bar was done" was run
+and program finished successfully
 ~~~
 
 
@@ -545,16 +545,16 @@ combinations.
 
 ~~~scenario
 given file allkeywords.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen allkeywords.md -o foo.pdf
 then file foo.pdf exists
 when I run sp-codegen --run allkeywords.md -o test.py
 then scenario "All keywords" was run
-then step "given precondition foo" was run
-then step "when I do bar" was run
-then step "then bar was done" was run
-then program finished successfully
+and step "given precondition foo" was run
+and step "when I do bar" was run
+and step "then bar was done" was run
+and program finished successfully
 ~~~
 
 ~~~{#allkeywords.md .file .markdown .numberLines}
@@ -577,6 +577,39 @@ but foobar was done
 ```
 ~~~
 
+### Keyword aliases
+
+~~~scenario
+given file aliases.md
+and file b.yaml
+and file f.py
+when I run sp-docgen aliases.md -o aliases.html
+then file aliases.html matches /given<[^>]*> precondition foo/
+and file aliases.html matches /when<[^>]*> I do bar/
+and file aliases.html matches /and<[^>]*> I do foobar/
+and file aliases.html matches /then<[^>]*> bar was done/
+and file aliases.html matches /but<[^>]*> foobar was done/
+and program finished successfully
+~~~
+
+~~~{#aliases.md .file .markdown .numberLines}
+---
+title: Keyword aliasesG
+bindings: b.yaml
+functions: f.py
+...
+
+# Aliases
+
+```scenario
+given precondition foo
+when I do bar
+and I do foobar
+then bar was done
+but foobar was done
+```
+~~~
+
 ### Misuse of continuation keywords
 
 When continuation keywords (`and` and `but`) are used, they have to not be
@@ -586,8 +619,8 @@ be continuing.
 
 ~~~scenario
 given file continuationmisuse.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen continuationmisuse.md -o foo.pdf
 then file foo.pdf exists
 when I try to run sp-codegen --run continuationmisuse.md -o test.py
@@ -620,18 +653,18 @@ This scenario verifies that empty lines in scenarios are ignored.
 
 ~~~scenario
 given file emptylines.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen emptylines.md -o emptylines.pdf
 then file emptylines.pdf exists
 when I run sp-docgen emptylines.md -o emptylines.html
 then file emptylines.html exists
 when I run sp-codegen --run emptylines.md -o test.py
 then scenario "Simple" was run
-then step "given precondition foo" was run
-then step "when I do bar" was run
-then step "then bar was done" was run
-then program finished successfully
+and step "given precondition foo" was run
+and step "when I do bar" was run
+and step "then bar was done" was run
+and program finished successfully
 ~~~
 
 
@@ -746,27 +779,27 @@ programs that monitor the output file for changes.
 
 ~~~scenario
 given file simple.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen simple.md -o simple.pdf
 then file simple.pdf exists
 when I remember the metadata for simple.pdf
-when I run sp-docgen simple.md -o simple.pdf
+and I run sp-docgen simple.md -o simple.pdf
 then simple.pdf has the same metadata as before
-then only files simple.md, b.yaml, f.py, simple.pdf exist
+and only files simple.md, b.yaml, f.py, simple.pdf exist
 ~~~
 
 ### Do typeset if output is older than markdown
 
 ~~~scenario
 given file simple.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen simple.md -o simple.pdf
 then file simple.pdf exists
 when I remember the metadata for simple.pdf
-when I touch simple.md
-when I run sp-docgen simple.md -o simple.pdf
+and I touch simple.md
+and I run sp-docgen simple.md -o simple.pdf
 then simple.pdf has changed from before
 ~~~
 
@@ -774,13 +807,13 @@ then simple.pdf has changed from before
 
 ~~~scenario
 given file simple.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen simple.md -o simple.pdf
 then file simple.pdf exists
 when I remember the metadata for simple.pdf
-when I touch f.py
-when I run sp-docgen simple.md -o simple.pdf
+and I touch f.py
+and I run sp-docgen simple.md -o simple.pdf
 then simple.pdf has changed from before
 ~~~
 
@@ -788,13 +821,13 @@ then simple.pdf has changed from before
 
 ~~~scenario
 given file simple.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-docgen simple.md -o simple.pdf
 then file simple.pdf exists
 when I remember the metadata for simple.pdf
-when I touch b.yaml
-when I run sp-docgen simple.md -o simple.pdf
+and I touch b.yaml
+and I run sp-docgen simple.md -o simple.pdf
 then simple.pdf has changed from before
 ~~~
 
@@ -811,11 +844,11 @@ higher level starts a new scenario.
 
 ~~~scenario
 given file scenarioislowest.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-codegen --run scenarioislowest.md -o test.py
 then scenario "heading 1.1.1" was run
-then program finished successfully
+and program finished successfully
 ~~~
 
 ~~~~{#scenarioislowest.md .file .markdown .numberLines}
@@ -839,11 +872,11 @@ given precondition foo
 
 ~~~scenario
 given file subisnotnewscenario.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-codegen --run subisnotnewscenario.md -o test.py
 then scenario "heading 1.1a" was run
-then program finished successfully
+and program finished successfully
 ~~~
 
 ~~~~{#subisnotnewscenario.md .file .markdown .numberLines}
@@ -870,12 +903,12 @@ given precondition foo
 
 ~~~scenario
 given file samelevelisnewscenario.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-codegen --run samelevelisnewscenario.md -o test.py
 then scenario "heading 1.1.1" was run
-then scenario "heading 1.1.2" was run
-then program finished successfully
+and scenario "heading 1.1.2" was run
+and program finished successfully
 ~~~
 
 ~~~~{#samelevelisnewscenario.md .file .markdown .numberLines}
@@ -905,12 +938,12 @@ given precondition foo
 
 ~~~scenario
 given file higherisnewscenario.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-codegen --run higherisnewscenario.md -o test.py
 then scenario "heading 1.1.1" was run
-then scenario "heading 1.2" was run
-then program finished successfully
+and scenario "heading 1.2" was run
+and program finished successfully
 ~~~
 
 ~~~~{#higherisnewscenario.md .file .markdown .numberLines}
@@ -951,12 +984,12 @@ chosen scenarios.
 
 ~~~scenario
 given file twoscenarios-python.md
-given file b.yaml
-given file f.py
+and file b.yaml
+and file f.py
 when I run sp-codegen twoscenarios-python.md -o test.py
 and I run python3 test.py on
 then scenario "One" was run
-then scenario "Two" was not run
+and scenario "Two" was not run
 and program finished successfully
 ~~~
 
@@ -991,12 +1024,12 @@ chosen scenarios.
 
 ~~~scenario
 given file twoscenarios-bash.md
-given file b.yaml
-given file f.sh
+and file b.yaml
+and file f.sh
 when I run sp-codegen twoscenarios-bash.md -o test.sh
 and I run bash test.sh on
 then scenario "One" was run
-then scenario "Two" was not run
+and scenario "Two" was not run
 and program finished successfully
 ~~~
 
@@ -1119,10 +1152,10 @@ specified.
 given file metadate.md
 when I run sp-docgen metadate.md -o metadate.html
 then file metadate.html exists
-then file metadate.html contains "<title>The Fabulous Title</title>"
-then file metadate.html contains "Alfred Pennyworth"
-then file metadate.html contains "Geoffrey Butler"
-then file metadate.html contains "WIP"
+and file metadate.html contains "<title>The Fabulous Title</title>"
+and file metadate.html contains "Alfred Pennyworth"
+and file metadate.html contains "Geoffrey Butler"
+and file metadate.html contains "WIP"
 ~~~
 
 ~~~{#metadate.md .file .markdown .numberLines}
@@ -1145,10 +1178,10 @@ This scenario tests that the `--date` command line option is used.
 given file dateless.md
 when I run sp-docgen dateless.md -o dateoption.html --date=FANCYDATE
 then file dateoption.html exists
-then file dateoption.html contains "<title>The Fabulous Title</title>" 
-then file dateoption.html contains "Alfred Pennyworth"
-then file dateoption.html contains "Geoffrey Butler"
-then file dateoption.html contains "FANCYDATE"
+and file dateoption.html contains "<title>The Fabulous Title</title>" 
+and file dateoption.html contains "Alfred Pennyworth"
+and file dateoption.html contains "Geoffrey Butler"
+and file dateoption.html contains "FANCYDATE"
 ~~~
 
 ~~~{#dateless.md .file .markdown .numberLines}
@@ -1171,13 +1204,13 @@ modification time of the input file, and shall have the date in ISO
 
 ~~~scenario
 given file dateless.md
-given file dateless.md has modification time 2020-02-26 07:53:17
+and file dateless.md has modification time 2020-02-26 07:53:17
 when I run sp-docgen dateless.md -o mtime.html
 then file mtime.html exists
-then file mtime.html contains "<title>The Fabulous Title</title>"
-then file mtime.html contains "Alfred Pennyworth"
-then file mtime.html contains "Geoffrey Butler"
-then file mtime.html contains "2020-02-26 07:53"
+and file mtime.html contains "<title>The Fabulous Title</title>"
+and file mtime.html contains "Alfred Pennyworth"
+and file mtime.html contains "Geoffrey Butler"
+and file mtime.html contains "2020-02-26 07:53"
 ~~~
 
 ### Using as a Pandoc filter
@@ -1237,19 +1270,19 @@ or functions files.
 
 ~~~scenario
 given file images.md
-given file b.yaml
-given file f.py
-given file foo.bib
-given file bar.bib
+and file b.yaml
+and file f.py
+and file foo.bib
+and file bar.bib
 when I run sp-meta images.md
 then output matches /source: images.md/
-then output matches /source: b.yaml/
-then output matches /source: f.py/
-then output matches /source: foo.bib/
-then output matches /source: bar.bib/
-then output matches /source: image.gif/
-then output matches /bindings: b.yaml/
-then output matches /functions: f.py/
+and output matches /source: b.yaml/
+and output matches /source: f.py/
+and output matches /source: foo.bib/
+and output matches /source: bar.bib/
+and output matches /source: image.gif/
+and output matches /bindings: b.yaml/
+and output matches /functions: f.py/
 ~~~
 
 
@@ -1317,7 +1350,7 @@ This is the embedded file.
 given file onefiletwice.md
 when I try to run sp-docgen onefiletwice.md -o onefiletwice.html
 then exit code is non-zero
-then file onefiletwice.html does not exist
+and file onefiletwice.html does not exist
 ~~~
 
 ~~~~{#onefiletwice.md .file .markdown .numberLines}
@@ -1341,7 +1374,7 @@ This is another embedded file, and has the same name.
 given file casediff.md
 when I try to run sp-docgen casediff.md -o casediff.html
 then exit code is non-zero
-then file casediff.html does not exist
+and file casediff.html does not exist
 ~~~
 
 ~~~~{#casediff.md .file .markdown .numberLines}
@@ -1381,7 +1414,7 @@ HTML output, not referenced as an external image.
 
 ~~~scenario
 given file dot.md
-given file b.yaml
+and file b.yaml
 when I run pandoc --filter sp-filter dot.md -o dot.html
 then file dot.html matches /img src="data:image/svg\+xml;base64,/
 ~~~
@@ -1422,7 +1455,7 @@ the HTML output, not referenced as an external image.
 
 ~~~scenario
 given file plantuml.md
-given file b.yaml
+and file b.yaml
 when I run pandoc --filter sp-filter plantuml.md -o plantuml.html
 then file plantuml.html matches /img src="data:image/svg\+xml;base64,/
 ~~~
@@ -1502,7 +1535,7 @@ HTML output, not referenced as an external image.
 
 ~~~scenario
 given file roadmap.md
-given file b.yaml
+and file b.yaml
 when I run pandoc --filter sp-filter roadmap.md -o roadmap.html
 then file roadmap.html matches /img src="data:image/svg\+xml;base64,/
 ~~~
@@ -1556,6 +1589,7 @@ blocked:
 ~~~
 ~~~~~~~~
 
+
 ### Class name validation
 
 When Subplot loads a document it will validate that the block classes