Syntax

Comparing LaTeX and JSON

Each example below compares the LaTeX source with the JSON snippet syntax:

• LaTeX code: the source you want to appear in your .tex file after the snippet expands.
• Snippet syntax: the JSON entry you put inside latex.json.

The main difference is escaping. In LaTeX source, a command uses one backslash. Inside a JSON snippet string, that backslash must be written as two backslashes.

\begin{equation*}

"\\begin{equation*}"

Use $1, $2, and $3 for tab stops. Use $0 for the final cursor position. Use ${1:label} when you want editable placeholder text.

When you add more than one snippet to latex.json, keep all entries inside the outer { ... } object and separate neighboring entries with commas.

Math delimiters

Use these LaTeX patterns for common math delimiters.

\left\| x \right\|
\left\vert x \right\vert
\left\langle x \right\rangle

Put these snippet entries in latex.json.

"norm": {
  "prefix": "@11",
  "body": "\\left\\| $1 \\right\\| $0"
},
"absolute value": {
  "prefix": "@1",
  "body": "\\left\\vert $1 \\right\\vert $0"
},
"angle brackets": {
  "prefix": "@<",
  "body": "\\left\\langle $1 \\right\\rangle $0"
}

Math structures

Use this LaTeX pattern for a 2x2 matrix.

\begin{bmatrix}
    a & b \\
    c & d
\end{bmatrix}

Put this snippet entry in latex.json.

"2x2 Matrix": {
  "prefix": "mtx2",
  "body": [
    "\\begin{bmatrix}",
    "    ${1:a} & ${2:b} \\\\",
    "    ${3:c} & ${4:d}",
    "\\end{bmatrix}$0"
  ]
}

Use this LaTeX pattern for an integral.

\int_{a}^{b}  f(x)  \, dx

Put this snippet entry in latex.json.

"Integration": {
  "prefix": "int",
  "body": "\\int_{${1:a}}^{${2:b}}  ${3:f(x)}  \\, d${4:x} $0"
}

Display equations

Use this LaTeX pattern for an unnumbered display equation.

\begin{equation*}
    ...
\end{equation*}

Put this snippet entry in latex.json.

"Equation without numbering": {
  "prefix": "eq",
  "body": [
    "\\begin{equation*}",
    "    $0",
    "\\end{equation*}",
    ""
  ]
}

When you type eq, VS Code inserts the environment and places the cursor inside it.

Use this LaTeX pattern when the equation needs a label.

\begin{equation}    \label{eq:main-estimate}
    ...
\end{equation}

Put this snippet entry in latex.json.

"Equation with numbering": {
  "prefix": "eqn",
  "body": [
    "\\begin{equation}    \\label{eq:${1:main-estimate}}",
    "    $0",
    "\\end{equation}",
    ""
  ]
}

The first tab stop fills the label. The final cursor position stays inside the equation body.

Alignments

Use this LaTeX pattern for a multi-line calculation without equation numbers.

\begin{align*}
    ...
    &= ...
    &= ...
\end{align*}

Put this snippet entry in latex.json.

"Align without numbering": {
  "prefix": "ag",
  "body": [
    "\\begin{align*}",
    "    $1",
    "    &${2:=} $3   \\\\",
    "    &${4:=} $5",
    "\\end{align*}",
    "",
    "$0"
  ]
}

The \\\\ in the snippet syntax becomes \\ in the LaTeX file. That is the line break command used by align.

Use this LaTeX pattern when the important lines need labels.

\begin{align}
    ...
    &= ...    \label{ag:first-step}    \\
    &= ...    \label{ag:second-step}
\end{align}

Put this snippet entry in latex.json.

"Align with numbering": {
  "prefix": "agn",
  "body": [
    "\\begin{align}",
    "    $1",
    "    &${2:=} $3    \\label{ag:${4:first-step}}    \\\\",
    "    &${5:=} $6    \\label{ag:${7:second-step}}",
    "\\end{align}",
    "",
    "$0"
  ]
}

Use unnumbered alignment while drafting. Switch to numbered alignment only when another paragraph needs to refer to a specific line.

Theorem blocks and proofs

Use this LaTeX pattern for a theorem-like block.

\begin{theorem}    \label{thm:main-result}
    ...
\end{theorem}

Put this snippet entry in latex.json.

"Theorem": {
  "prefix": "thm",
  "body": [
    "\\begin{theorem}    \\label{thm:${1:main-result}}",
    "    $0",
    "\\end{theorem}",
    ""
  ]
}

The same pattern works for definitions, propositions, lemmas, and corollaries. Change the environment name, prefix, and label prefix together.

Use this LaTeX pattern for a proof.

\begin{proof}
    ...
\end{proof}

Put this snippet entry in latex.json.

"Proof": {
  "prefix": "pf",
  "body": [
    "\\begin{proof}",
    "    $0",
    "\\end{proof}"
  ]
}

Keep the label prefix meaningful: thm:, lem:, prop:, def:, and crl: make references easier to scan.

Cases and piecewise definitions

Use this LaTeX pattern for a two-case definition.

\begin{equation*}
    f(x) =
    \begin{cases}
        ...    &    \text{if } ...,    \\
        ...    &    \text{if } ...
    \end{cases}
\end{equation*}

Put this snippet entry in latex.json.

"Two cases": {
  "prefix": "css2",
  "body": [
    "\\begin{equation*}",
    "    ${1:f(x)}",
    "    \\begin{cases}",
    "        $2    &    \\text{${3:if} } $4,    \\\\",
    "        $5    &    \\text{${6:if} } $7",
    "    \\end{cases}",
    "\\end{equation*}",
    "$0"
  ]
}

Keep the displayed formula short. If a condition is long, explain it before the display and keep the case split readable.

Figures

Use this LaTeX pattern for a figure.

\begin{figure}[htbp]
    \centering
    \includegraphics[width=0.8\linewidth]{figure-filename}
    \caption{Caption text}
    \label{fig:main-figure}
\end{figure}

Put this snippet entry in latex.json.

"Inserting a picture": {
  "prefix": "pct",
  "body": [
    "\\begin{figure}[htbp]",
    "    \\centering",
    "    \\includegraphics[width=${1:0.8}\\linewidth]{${2:figure-filename}}",
    "    \\caption{${3:Caption text}}",
    "    \\label{fig:${4:main-figure}}",
    "\\end{figure}",
    "",
    "$0"
  ]
}

The first placeholder controls the width. The second chooses the file. The third writes the caption. The fourth sets the figure label.

Texts

Use these LaTeX patterns for common text snippets.

Fr\'echet
\mathbb{R}
\qquad\text{and}\qquad

Put these snippet entries in latex.json.

"Frechet": {
  "prefix": "Fre",
  "body": "Fr\\'echet$0"
},
"Real numbers": {
  "prefix": "R",
  "body": "\\mathbb{R}$0"
},
"And in line": {
  "prefix": "qqand",
  "body": [
    "",
    "\\qquad\\text{${1:and}}\\qquad",
    "$0"
  ]
}

For short inline snippets, choose prefixes that do not appear inside ordinary words. A convenient shortcut is only useful if it does not expand by accident.

Build snippets from LaTeX code you already understand. The snippet should save repeated typing, not hide syntax that you still need to inspect and edit.