07 / Reference

Reference

Shortcuts, commands, menus, file formats and vocabulary — the things you look up rather than read.

Keyboard shortcuts

Keys	Action
`Ctrl` + `N`	New workspace
`Ctrl` + `O`	Open a `.blc` file
`Ctrl` + `S`	Save workspace as…
`Ctrl` + `Z`	Undo
`Ctrl` + `Shift` + `Z`	Redo
`Ctrl` + `B`	Toggle the blocks sidebar
`Ctrl` + `Alt` + `C`	Toggle the code / Inspector panel
`Ctrl` + `J`	Toggle the bottom panel
`Ctrl` + `Shift` + `B`	Refresh generated output
`Ctrl` + `Shift` + `P` or `F1`	Command palette
`F11`	Presentation perspective
`/`	Focus the toolbox search field
`?`	Open the Keyboard Shortcuts dialog
`Esc`	Close the innermost thing that is open — see below

Escape closes one layer at a time

Esc works innermost-first rather than dismissing everything at once, and it returns focus to whatever opened the layer it closed. The order is: the Settings dialog, then the command palette, then the Examples menu, then the Renderer menu, then any other open header menu, then the compact menu drawer, then the toolbox overlay, then the Inspector overlay, then the bottom panel. The last three only apply at narrow widths, where those panels are overlays rather than columns.

Inside a menu, a tab strip or the program outline, the arrow keys move between items, Home and End jump to the ends, and ↓ on a closed menu opens it at the first item while ↑ opens it at the last.

Command palette

Ctrl + Shift + P. Commands are grouped by prefix; typing the prefix filters to that group.

Prefix	Commands
`File:`	New Workspace · Open Workspace… · Save Workspace As… · Recover Local Autosave · Show Menu
`Edit:`	Undo · Redo
`Build:`	Refresh Generated Output
`View:`	Toggle Primary Sidebar · Toggle Code and Inspector · Toggle Bottom Panel · Show Blocks · Show Problems · Show Code · Show Inferred Types · Show Typing Derivation · Show Outline · Show Output
`Run:`	Call-by-Structure Trace · Call-by-Value Trace · CSEK Machine · Lockstep Debugger · Re-run Active Semantic View · Arrange Reduction Steps
`Perspective:`	Edit · Debug · Type Analysis · Presentation
`Preferences:`	Settings · Toggle Color Theme
`Workspace:`	Zoom In · Zoom Out · Zoom to Fit
`Code:`	Synchronize from Workspace
`Help:`	Keyboard Shortcuts

Menu map

Menu	Contents
File	New Workspace · Open… · Save As… · Recover Autosave
Examples	The twelve programs listed in Overview
View	The three panel toggles, plus the four perspectives
Renderer	Tude (square, the project renderer) · Zelos (rounded) · Thrasos (classic)
More	Undo · Redo · Call-by-Structure Trace · Call-by-Value Trace · Lockstep Debugger · Refresh Generated Output · Show Inferred Types · Show Problems · Settings · Command Palette… · Keyboard Shortcuts · About Block Lambda

The right-click menu on an application block adds Show Type and Value, Evaluate – Call-by-Structure and Evaluate – Call-by-Value.

Dialogs

Dialog	Opened by	Holds
Settings	More → Settings, or `Preferences: Settings`	Three sections only: colour theme, perspective, and the autosave interval. The renderer is not here — it has its own header menu.
Keyboard Shortcuts	`?`, More → Keyboard Shortcuts, or `Help: Keyboard Shortcuts`	The shortcut list, plus prose sections on what `Esc` does and on arrow-key navigation inside menus, tab strips and the outline.
Block Info	Show Type and Value on a block's right-click menu	The selected block's type and value. The value section names the strategy that produced it — Value (Call-by-Structure) — so the number is never ambiguous.
About Block Lambda	More → About Block Lambda	Version and licence. This help is written against the version reported here.

The Block Info dialog for an Application block, listing Block as Application, Type as int, a section headed Value in brackets Call-by-Structure giving 24, and Status as Well typed. — **Fig. 2** *Block Info*. The value heading names its strategy — *Value (Call-by-Structure)* — so a number here is never ambiguous about how it was produced.

File formats

Format	Holds
`.blc`	A Block Lambda workspace. Saved and opened locally — nothing is uploaded.
Local storage	The rolling autosave backup, plus your layout, theme, renderer, autosave interval and active tabs. Restored defensively: a malformed payload falls back to the default layout rather than failing to start.
Lambda text	Not a file format, but the Code tab round-trips the term as text, so you can paste a program in or copy one out.

Glossary

Term	Means
ANF	A-normal form — every intermediate result is bound to a name.
β-reduction	Applying a function by substituting the argument for the parameter.
Call-by-Structure	B-Lambda's default strategy. Strict in its argument, like Call-by-Value, but it substitutes the structured value — the value paired with the expression it came from — instead of the bare value. Same work, more of the derivation left visible.
Call-by-Value	Reduce the argument to a value, then substitute. The work happens once.
CSEK machine	An abstract machine with Control, Structure, Environment and Kontinuation. The S is the structured value, not a store — B-Lambda has no heap.
CPS	Continuation-passing style — control flow made explicit as a passed-in continuation.
Closure conversion	Turning a function that captures free variables into a code pointer plus an explicit captured environment.
Kontinuation	The pending work: what the machine will do with the value it is currently computing. Spelled with a K by convention, so the machine's initials work out.
Lockstep	The view that runs substitution, the CSEK machine and the register VM together and checks they agree.
Normal form	A term with no reducible sub-term left. A λ is already a value, so its body is not reduced.
Salient rule	A human-visible reduction — `beta`, `if-true`, `if-false`, `prim …`. The unit the substitution trace counts.
SSA	Static single assignment — each register is written exactly once, which is what makes the φ-node projection meaningful.
Structured value	A computed value paired with the block it was computed from, written `V_p ⊗ V_v`. What Call-by-Structure substitutes, and the S in CSEK.
Thunk	An unevaluated block plus the environment it should be evaluated in. Now used only for `letrec`, whose binding is cyclic and is re-entered at each use; ordinary arguments are evaluated strictly and bound as structured values.
Tude	B-Lambda's own Blockly renderer: Zelos connections, square corners.

Elsewhere in the workshop

MnL help — the functional language that shares Call-by-Structure and the Lockstep view. B-MJ help — MiniJava, where the machine gains a store and the interesting question becomes aliasing.

Block Lambda is developed at L-Workshop. This help was written against Block Lambda 1.2.0.