This document explains what a user of TalkTex should say to obtain certain Latex output.
TalkTex uses its own TalkTex grammar. This grammar defines how phrases, which are strings of words spoken by the user, are translated to Latex source code. In order to do so, TalkTex maintains its own vocabulary: the set of minimal phrases which build up our grammar. The TalkTex vocabulary consists of two kinds of phrases: terminals and keywords.
Terminals are (minimal) phrases which have a direct translation to Latex source code, which we call the target. An example is "union", whose target is "\cup". A minimal phrase may consist out of multiple words. For example we also have the terminal "less than" whose target is "<". A key property of terminals is that their translations do not depend on the context of the spoken words.
Keywords are (minimal) phrases which do not have a direct translation to Latex source code, but which do contribute to the meaning of a spoken sentence. An example is the keyword "end". This keyword is used to indicate where the scope of a certain expression ends. Consider the phrase "sine of x plus one", which is translated to "\sin(x+1)". If we would want to obtain "\sin(x)+1" as output, we could say "sine of x end plus one". Here the keyword "end" indicates that the scope of the expression of which we take the sine ends. Also note that the keyword "end" itself does not have a direct translation into Latex source code.
Our grammar allows a user to build up more complicated sentences using terminals and keywords. Rules for how to build up more complicated (parts of) sentences are defined by constructs. A construct consists of five pieces of information, called its type, phrase, target, priority and synonyms. The type declares what kind of construct this is. The phrase indicates the words spoken by the user and the target gives the corresponding Latex source code translation. The priority indicates in which order this construct should be applied with respect to other available constructs: higher priority constructs will always be applied first. The synonyms indicate alternative phrase that the user could say to also obtain the same Latex source code. We clarify the above by means of examples below.
We start off with the simplest kind of example, namely we will define two terminal constructs. These are constructs defining terminals. Construct definitions are denoted as follows.
| phrase | target | priority | synonyms |
|---|---|---|---|
| divided by | / | 10 | |
| greater equal | \geq | 11 | bigger equal, larger equal |
| equal | = | 10 | equals |
The definition above defines three constructs: the "divided by"-construct, the "greater equal"-construct and the "equal"-construct. Their types are all "BINOP", indicating that these are binary oparators. The first construct has phrase "divided by" and target "/". This means that when a user says "divided by", TalkTex will translate this to the Latex source code "/". This definition hence also defines the phrase "divided by" to be a terminal. The "greater equal"-construct has the higher priority 11, while the other two have priority 10. This ensures that we do not interpret the phrase "equal" as an equal sign if the word "greater" directly precedes it. The "greater equal"-construct has two synonyms: "bigger equal" and "larger equal". This defines these two phrases to be terminals as well and both are translated to the Latex source code "/" as well.
Next we will look at general constructs. Next to terminals and keywords, constructs may also use phrases of other constructs in their own phrases. As our example we will consider VARIABLE-constructs (of type "VARIABLE"). For this we first need a few new terminal constructs. We simplified the definition of LETTER a little bit for this exposition. See the reference for the full definition.
| phrase | target | priority | synonyms |
|---|---|---|---|
| a | a | 10 | |
| capital a | A | 10 | |
| alpha | \alpha | 10 |
| phrase | target | priority | synonyms |
|---|---|---|---|
| bold | \mathbb | 10 | |
| caligraphic | \mathcal | 10 |
| phrase | target | priority | synonyms |
|---|---|---|---|
| tilde | \tilde | 10 | |
| hat | \hat | 10 | |
| bar | \bar | 10 |
Above we have defined LETTER, TYPESETTING and ACCENT constructs. There actually exist more letters, accents and typesettings than the ones listed above. But we keep it small here. Now we can define variables in TalkTex, i.e. constructs of type VARIABLE:
| phrase | target | priority | synonyms |
|---|---|---|---|
| LETTER[L] | L | 9 | |
| TYPESETTING[T] VARIABLE[V] | T{ V } | 8 | |
| VARIABLE[V] ACCENT[A] | A{ V } | 7 |
The phrases above contain words in all-caps. These all caps words denote a construct of a specific type. For example the first construct defined above (with priority 6), states that its phrase can be the phrase of any LETTER construct. The notation [L] after LETTER creates an alias "L" for the target of the corresponding LETTER construct. This alias is used in the target specification. In this case it states that the target of this construct is the same as the target of the LETTER construct that was spoken. The phrase of the second construct consists of two parts: first a typesetting and then a variable. Aliases "T" and "A" are declared for the targets of the typesetting and the variable respectively. The target is defined in terms of these aliases. Note that we use raw latex source code mixed with these aliases. The constructs above provide us with the following translations.
| spoken phrase | Latex source code translation |
|---|---|
| alpha | \alpha |
| caligraphic capital a | \mathcal{ A } |
| alpha tilde | \tilde{ \alpha } |
| bold capital a hat | \hat{ \mathbb{ A } } |
Note that our priority definitions are relavant. If the second (i.e. priority 5) construct would have had priority 3 instead, then the last translation would have been "\mathbb{ \hat{ A } }".
As mentioned already, constructs may also be built using keywords. Let us give an example of how keywords and constructs can be used together to build complex constructs.
| phrase | target | priority | synonyms |
|---|---|---|---|
| function VARIABLE[F] from SYMBOL[A] to SYMBOL[B] | F: A \to B | 5 |
Above, the words in small letters ("function", "from" and "to") are keywords. These words should be pronounced literally by the user. In contrast, the capitalized words (e.g. "VARIABLE") indicate other constructs. Note also how we define three different aliases above ("F", "A" and "B"), all of whose parent constructs are of type VARIABLE. This allows us to distinguish them appropriately in the target definition. The definition above allows for example the following translation.
| spoken phrase | Latex source code translation |
|---|---|
| function f tilde from capital a to bold capital r | \tilde{ f }: A \to \mathbb{ R } |
TalkTex recognizes pauses in your speech in such a way that it removes the burden of saying "end" at the correct moments from the user. If a user takes a small pause between saying consecutive words in a sentence, then TalkTex will interpret that pause as if the user had said "end". This facilitates the following behaviour. Below "..." denotes a pause in the users speech.
| spoken phrase | Latex source code translation |
|---|---|
| sin of a plus b | \sin( a + b ) |
| sin of a ... plus b | \sin( a ) + b |
See the complete TalkTex grammar document for information on all the vocabulary and grammar rules of TalkTex. These enable the user to talk Tex in many ways. We end with a final example, which combines various constructs into a longer sentence.
| spoken phrase | Latex source code translation |
|---|---|
| sum from i equals zero to infinity sin of i | \sum_{i=0}^{\infty}\sin \left(i\right) |